Posted – July 1st, 2010
under CannaLogic
Leave a comment
– go to post


There are about 15 elements known to be essential to plant life. Carbon, hydrogen, and oxygen are absorbed from air and water. The remaining 12 elements are absorbed primarily from the soil, in mineral (inorganic) forms such as NO3- and K+. They constitute a natural part of soil that becomes available to the plant os organic matter decays and soil particles such as sand and clay dissolve.

Soil elements that are necessary for normal growth are called nutrients. The elements nitrogen (N), phosphorous (P), and potassium (K) are considered major nutrients. The three numbers that appear on all fertiliser packages give the available percentage of these three nutrients that the fertiliser contains; and always in the order N-P-K. For example, 10-2-0 means 10 percent N, 2 percent P (actually, 2 percent P2O5), and no K (actually, no K2O). Fertility is often measured by the amounts of major nutrients a soil contains. Relatively large amount of N-P=K are needed for lush growth.

Three other elements – calcium (Ca), sulphur (S), and magnesium (Mg) – are called secondary nutrients. Plants require less of these nutrients, and most cultivable soils contain adequate amounts for good growth.

Six remaining elements are called trace elements or micronutrients. As their name implies, they are needed in very small amounts. Commercial soils contain enough trace elements to sustain normal growth. The trace elements are also present in manures, humus, ash, and limestone.


The amount of nitrogen a soil can supply is the best indication of its fertility. Nitrogen, more than any other soil nutrient, is inextricably linked with the living ecosystem. Nitrogen is continually cycled through living systems: from soil to plants and back to the soil, primarily by the activity of soil microorganisms. Nitrogen is essential to all life. Nitrogen is a key element in the structure of amino acids, the molecules which make up proteins. These, and all other biomolecules, are synthesised by the plant. Chlorophyll, genetic material (for example, DNA), and numerous enzymes and plant hormones contain nitrogen. Hence, N is necessary for many of the plant's life processes.

Cannabis is a nitrophile, a lover of nitrogen. Given ample N, Cannabis will outgrow practically and plant. Ample nitrogen is associated with fast, lush growth, and the plant requires a steady supply of nitrogen throughout its life. Marijuana's requirements for N are highest during the vegetative growth stages.


P is a constituent of energy-transfer compounds such as NADP and ATP, and molecular complexes such as the genes. The energy compounds are necessary for photosynthesis, respiration, and synthesis of biomolecules. Cannabis takes up large amounts of P during germination and seedling stages. During flowering and seed set, Cannabis' need for phosphorous is also high.


K influences many plant processes, including photosynthesis and respiration, protein synthesis, and the uptake of nutrients. Just as with P, K uptake is highest during the earliest growth stages. K is associated with sturdy stems and resistance to disease in plants.


Ca functions as a coenzyme in the synthesis of fatty compounds and cell membranes, and is necessary for normal mitosis (replication of cells). Plants take up much more Ca than the small amount necessary for normal growth. Ca is not added to soil as a nutrient; is added to adjust the soil's chemistry or pH.


S is a constituent of certain amino acids and proteins. It is an important part of plant vitamins, such as biotin and thiamine, which are necessary for normal respiration and metabolism. (Plants synthesise all vitamins they need.) Most soils suitable for growing marijuana contain plenty of S.


Mg is involved in protein synthesis and metabolism of carbohydrates. Mg is the central element in the structure of chlorophyll molecules and hence has an important role in photosynthesis. Most mineral soils and commercial soils have a good supply of Mg.

Trace Elements

The trace elements (Fe, Mn, Mb, B, Cu, Zn) are particularly important in the coenzymes and catalysts of the plant's biochemistry. Many life processes, particularly the synthesis and degradation of molecules, energy transfer, and transport of compounds within the plant, depend on trace elements. Trace elements are not used in large quantities to spur growth, but are necessary in minute amounts for normal growth. Indoor soils rarely require an addition of trace elements.

All the nutrients are needed for normal growth. However, most of them are supplied by the potting soil. Ca, S, and the trace elements rarely present any problems. For most growers, fertilising will simply require periodic watering with a complete fertiliser, one that contains N, P, and K.

Application: Fertilising

To grow to a large size, marijuana requires a steady supply of nutrients. These can be added to the soil before planting or anytime during growth. Bulk fertilisers are added while the soil is mixed, as described in section 6. These include manures, composts, humus, and concentrated fertilisers, such as rose food. Once the plants are growing, never condition or mulch indoor soils with bulk fertilisers. they promote moulds and fungi and attract other pests to the garden. Concentrated fertilisers can damage the plants if they come in direct contact with the stem or roots.

While the plants are growing, nutrients are given in solution; they are dissolved in water, and the plants are watered as usual. Soluble fertilisers can be either organic or inorganic (chemical), and come in a wide range of concentrations and proportions of nutrients. Two organic fertilisers are liquid manure (about 1.5-1.0-1.5) and fish emulsion ((Some fish emulsion may contain whale by-products.)) (about 5-1-1). Chemical fertilisers commonly may have 20-20-20 or 5-10-5, or may contain only one nutrient, such as 16-0-0.

A 10-5-5 fertiliser is 20 percent soluble nutrients and 80 percent inert ingredients. a 30-10-10 has 50 percent available nutrients and 50 percent inert ingredients. There is approximately the same amount of N in one tsp. of 30-10-10 as in three tsps. of 10-5-5.

Actually, you can almost use any fertiliser, but the nitrogen content should be proportionately high, and there should be some P and L also present. For example, a 20-20-20 would work fine, as would a 12-6-6 or a 3-4-3, but not a 2-10-10 or a 5-10-0.

How much fertiliser to use and how often to fertilise depend primarily on the fertility of the soil and the size of the container relative to the size of the plant. Small plants in large pots usually do not need to be fertilised. Even in small pots, most plants do not need to be fertilised for at least the first month.

As the plants grow, they take nutrients from the soil, and these must be replaced to maintain vigorous growth. During the vegetative stage, even plants in large pots generally require some fertilising, particularly with N.

The rate of growth of indoor plants is usually limited by the amount of light and space, once adequate nutrients are supplied. At this point, an increase in nutrients will not increase growth. Your goal is to supply the plants with their nutritional needs without overfertilising and thus toxifying the soil.

Most fertilisers are designed for home use and have instructions for fertilising houseplants. Marijuana is not a houseplant, and it requires more nutrients than houseplants. The extra nutrients that it needs may be supplied by the use of large pots and a fertile soil mixture. In many cases, you will need to fertilise only in the dosages recommended on fertiliser packages for houseplants. For instance, Rapid-Gro (23-19-17) is popular among marijuana growers; use one tablespoon per gallon of water every two weeks.

A typical program for fertilising might be to fertilise during the fifth week of growth and every two weeks thereafter until flowering. Then discontinue fertilising (or give at one-half concentration) unless the plants show a definite need for nutrients. It is better to fertilise with a more diluted solution more often than to give concentrated doses at longer intervals. (For instance, if instructions call for one tablespoon of fertiliser per gallon once a month, use one-quarter tablespoon per gallon once a week.)

Make sure that a fertiliser is completely dissolved in the water before you apply it. Put the recommended amount of fertiliser in a clear glass bottle and mix with about one cup of water. Shake vigorously and then allow it to settle. If any particles of fertiliser are not dissolved, shake again before adding the rest of the water. If you have difficulty getting all the fertiliser to dissolve, first add hot top water. If the fertiliser still does not completely dissolve, you should use another fertiliser.

Never fertilise a dry soil or dry Soilless medium. If the medium is dry, first water with about one-half quart of plain water per pot. Let the pots sit for about 15 minutes so that the water is evenly dispersed in the pot. Then fertilise as usual.

It is difficult to give instruction for fertilising that will cover all garden situations. You want to supply the plant with its nutritive needs, but overfertilising con toxify the soil. Fertilising according to instructions for houseplants (both in frequency and concentration) should not toxify the soil. However, the plants may sometimes require more frequent or more concentrated fertilising. A good way to judge the plant's needs is not to fertilise one plant, double the fertiliser of another plant, and give the rest of the plants their normal dose. If the unfertilised plant grows more slowly, or shows symptoms of deficiencies, then probably all the plant are depending on soluble fertilisers and must be fertilised regularly. If the plants receiving the double dose grows faster than the other plants, increase the other plants' supply also. On the other hand, if there is little difference among the plants, then the soil is providing the plants with enough nutrients, and they either should not be fertilised or should be fertilised with a less-concentrated solution.

Because they are grown in a relatively small area, it is easy to overfertilise indoor plants. When plants are vigorous, look healthy, and are growing steadily, don't be anxious to fertilise, particularly if you have already fertilised several times with soluble fertilisers. Slow growth or symptoms of deficiencies clearly indicate the need for fertilising.


In an effort to do the best for their plants, some people actually do the worst. Overfertilising puts excessive amounts of nutrients in the soil, causing toxic soil conditions. Excessive amounts of one nutrient can interfere with the uptake of another nutrient, or change normal plant-soil relations. Since it takes time for a build-up to occur high concentrations of nutrients generally encourage excellent growth until the toxic level is reached.

It takes less N than other nutrients to toxify the soil; hence there is less margin for error when using N. Too much N changes the osmotic balance between plant and soil. Instead of water being drawn into the plant, water is drawn away and the plant dehydrates. The leaves feel limp even though the plant is well watered. The plant will soon die. This tips of the leaves die first and very rapidly the leaves change colour, usually to gold, but sometimes to a brown or green-grey. This change in the plants is faster, more dramatic, and more serious than for any kind of nutrient deficiency.

You can save the plants by immediately leaching the pots as soon as the condition is recognised. Place the pots outdoors or in a sink or bathtub. Discard the top inch or two of loose dirt. Run lukewarm water through the soil until a gallon of water for each two gallons of soil has passed through each pot. The leaves recover turgor in one or two days if the treatment works.

Foliar Feeding

Foliar feeding ((Nitrogen fertilisers are usually NO3 (nitrate) or NO2 (nitrite), substances which are also used to preserve food. They have been shown to undergo reactions to form carcinogenic substances (nitrosamines). As with eating food treated with nitrates and nitrites (hot dogs, sandwich meats, etc.), there is a possibility that such substances might be ingested by eating or smoking foliar-fed plants.)) (spraying the leaves with fertiliser) is a good way to give the plants nutrients without building up the amount of soluble substances in the soil. After the first month, foliar feed the plants with, for example, fish emulsion or a chemical fertiliser. Use any fertiliser that states it can be used for foliar feeding even if it says "not recommended for foliar feeding houseplants." Use a fine-mist sprayer, such as a clean Windex or Fantastik bottle. Dilute the fertiliser according to directions (fish emulsion at one tablespoon per gallon) and spray both sides of the leaves. When foliar feeding, you should spray the plants with plain water the next day, to dissolve unabsorbed nutrients and clean the plants.

Foliar spraying is also a good way to treat plants suffering from nutrient deficiencies. Some nutrient deficiencies actually are caused by the soil's chemistry, rather than by the absence of the nutrient in the soil. Addition of the necessary nutrient to the soil may not cure the plants' problem, because the nutrient becomes locked in the soil, or its uptake may be limited by high concentrations of other elements present in the soil. Foliar feeding is direct, and if the plant's deficiency symptoms do not begin to clear up, then the diagnosis is probably incorrect.

Nutrient Deficiencies

Before Diagnosing

Before you assume the marijuana plant has a nutrient deficiency, make sure the problem is not due to other causes. Examine the marijuana plant leaves, and along the stem and in the soil.

Even under the best conditions, not all leaves form perfectly or remain perfectly green. Small leaves that grew on the young seedling normally die within a month or two. Under artificial lights, bottom marijuana leaves may be shielded from the light, or be too far away from the light to carry on chlorosynthesis. These leaves will gradually turn pale or yellow, and may form brown areas as they die. However, healthy large leaves should remain green at least three to four feet below the plant tops, even on those plants under small light systems. Under low light, the lower-growing shoots as well as the large leaves on the main stem are affected. Some symptoms of nutrient deficiencies begin first at the bottom of the plant, but these symptoms generally affect the lower leaves on the main stem first, and the progress to the leaves on the branches.

Although some deficiency symptoms start on the lower, older leaves, others start at the growing shoots or at the top of the marijuana plants. This difference depends on whether or not the nutrient is mobile and can move from the older leaves to the active growing shoot. Deficiency symptoms of mobile nutrients start at the bottom of the plant. Conversely, deficiency symptoms of immobile nutrients first appear on the younger leaves or growing shoots at the top of the plant. N, P, K, Mg, B, and Mb are mobile in the plant. Mn and Zn are less mobile, and Ca, S, Fe, and Cu are generally immobile.

A dry atmosphere or wet soil may cause the blade tips to turn brown. Brown leaf tips also may indicate a nutrient deficiency, but in this case, more tissue will turn brown than just the end tips.

Chlorosis and necrosis are two terms which describe symptoms of disease in plants. Chlorosis means lacking green (chlorophyll). Chlorotic marijuana leaves are pale green to yellow or white. Chlorotic leaves often show some recovery after the necessary nutrient is supplied. Necrosis means that the tissue is dead. Dead tissue can be gold, rust, brown, or grey. It is dry and crumbles when squeezed. Necrotic tissue cannot recover.

Symptoms of deficiencies of either N, P, or K have the following in common: all involve some yellowing and necrosis of the lower leaves, and all are accompanied by red/purple colour in stems and petioles. The simplest way to remedy these deficiencies is to fertilise with a complete fertiliser containing nearly equal proportions of three nutrients.


N is the most common deficiency of Cannabis indoors or out. Nitrogen deficiencies may be quite subtle, particularly outdoors, where the soil may continuously provide a small amount of nitrogen. In this case the opt of the plant will appear healthy, and the plant will grow steadily, but at a slow pace. The deficiency becomes more apparent with growth, as more and more of the lower leaves yellow and fall. The first sign is a gradual, uniform yellowing of the large, lower leaves. Once the leaf yellow, necrotic tips and areas form as the leaves dry to a gold or rust colour. In small pots, the whole plant may appear pale (or lime colour) before many bottom leaves are affected to the point that they yellow or die. Symptoms that accompany N deficiency include red stems and petioles, smaller leaves, slow growth, and a smaller, sparse profile. Usually there is a rapid yellowing and loss of the lower leaves that progresses quickly to the top of the plant unless nitrogen is soon added.

Remedy by fertilising with any soluble N fertiliser or with a complete fertiliser that is high in N. If your diagnosis is correct, some recovery should be visible in three or four days. Pale leaves will regain some colour but not increase in size. New growth will be much more vigorous and new stems and petioles will have normal green colour.

Indoors, you should expect plants to need N fertilisation a few times during growth. Once a plant shows N deficiency, you should fertilise regularly to maintain healthy and vigorous growth. Fertilise at about one-half the concentration recommended for Soilless mixtures. Increase the treatment only if the plants show symptoms again. Once the plants are flowering, you may choose not to fertilise if the plants are vigorous. They will have enough N to complete flowering and you don't want to chance toxifying the soil at this late date.


P deficiency is not common indoors, but may appear outdoors, particularly in dry, alkaline soils or in depleted soils, or during cool weather. Phosphorus deficiency is characterised by slow and sometimes stunted growth. Leaves overall are smaller and dark green; red colour appears in petioles and stems. The leaves may also develop red or purple colour starting on the veins of the underside of the leaf. Generally the tips of most of the leaf blades on the lower portion of the plant die before the leaves lose colour. Lower leaves slowly turn yellow before they die. Remedy with any soluble P-containing fertiliser. Affected leaves do not show much recovery, but the plant should perk up, and the symptoms do not progress.


K deficiencies sometimes show on indoor marijuana plants even when there is apparently enough supplied for normal growth. Often, potassium-deficient marijuana plants are the tallest ((Potassium is associated with apical dominance in some plant species.)) and appear to be the most vigorous. Starting on the large lower leaves, the tips of the blades brown and die. Necrotic areas or spots form on the blades, particularly along the margins. Sometimes the leaves are spattered with chlorotic tissue before necrosis develops, and the leaves look pale or yellow. Symptoms may appear on indoor plants grown in a soil rich in organic material. This may be due to high salinity (Na) of some manures or composts used in the soil. Red stems and petioles accompany potassium deficiencies. K deficiencies that could seriously affect your crop rarely occur with indoor soils. However, mild symptoms are quite common. Usually the plants grow very well except for some necrotic spotting or areas on the older leaves. (This condition is primarily and aesthetic problem, and you may choose not to fertilise. See 19.3.)

K deficiencies can be treated with any fertiliser that contains potassium. Wood ashes dissolved in water are a handy source of potassium. Recovery is slow. New growth will not have the red colour, and leaves will stop spotting after a couple of weeks. In a K-deficient soil, much of the added potassium is absorbed by the soil until a chemical balance is reached. Then additional potassium becomes readily available to the plant.


Ca deficiencies are rare and do not occur if you have added any lime compound or wood ash. But calcium is added primarily to regulate soil chemistry and pH. Make sure that you add lime to soil mixtures when adding manures, cottonseed meal, or other acidic bulk fertilisers. An excess of acidic soil additives may create magnesium or iron deficiencies, or very slow, stunted growth. Remedy by adding one teaspoon of dolomitic lime per quart of water until the plants show marked improvement. Periodically fertilise with a complete fertiliser. Foliar feeding is most beneficial until the soil's chemistry reaches a new balance.


S is plentiful in both organic and mineral soils. Liming and good aeration increases S availability. Hence S deficiencies should not occur in soils that are suitable for growing marijuana. However, sulfur deficiencies sometimes can be confused with N deficiencies and may also occur because of an excess of other nutrients in the soil solution. Sulfur-deficiency symptoms usually start at the top of the plant. There is a general yellowing of the new leaves. In pots, the whole plant may lose some green colour. Both sulfur and Mg deficiencies can be treated with the same compound, epsom salts (MgSO4). Epsom salts, or bathing salts are inexpensive and available at drug stores.


Mg deficiencies are fairly common. They frequently occur in Soilless mixtures, since many otherwise all-purpose fertilisers do not contain Mg. Magnesium deficiencies also occur in mixtures that contain very large amounts of Ca or Cl. Symptoms of Mg deficiency occur first on the lower leaves. There is chlorosis of tissue between the veins, which remain green, and starting from the tips the blades die and usually curl upward. Purple colour builds up on stems and petioles.

A plant in a pot may lose much of its colour in a matter of weeks. You may first notice Mg symptoms at the top of the plant. The leaves in the growing shoot are lime-coloured. In extreme cases, all the leaves turn practically white, with green veins. Iron deficiency looks much the same, but a sure indication of Mg deficiency is that a good portion of the leaf blades die and curl. Treat Mg symptoms with one-half teaspoon of epsom salts to each quart of water, and water as usual. The top leaves recover their green colour within four days, and all but the most damaged should recover gradually. Continue to fertilise with epsom salts as needed until the plants are flowering well. If you are using soilless mixtures, include epsom salts regularly with the complete mixture. Because Mg deficiencies may indicate interference from other nutrients, foliar-spray with Mg to check your diagnosis if the plants are not obviously recovering.


Fe deficiency rarely occurs with indoor mixtures. Iron is naturally plentiful in most soils, and is most likely to be deficient when the soil is very acid or alkaline. Under these conditions, which sometimes occur in moist eastern soil outdoors, the iron becomes insoluble. Remedies include adjusting the Ph before planting; addition of rusty water; or driving a nail into the stem. Commercial Fe preparations are also available. If the soil is acidic, use chelated iron, which is available to the plants under acidic conditions.

Symptoms of iron deficiency are usually distinct. Symptoms appear first on the new growing shoots. The leaves are chlorotic between the veins, which remain dark green and stand out as a green network. To distinguish between Mg and Fe deficiencies, check the lower leaves for symptoms. Iron symptoms are usually most prominent on the growing shoots. Mg deficiencies will also show in the lower leaves. If many of the lower leaves have been spotting or dying, the deficiency is probably Mg. Mg deficiencies are much more common than iron deficiencies in marijuana.

Other Trace Elements

The following deficiencies are quite rare. Trace elements are needed in extremely small amounts, and often enough of them are present as impurities in fertilisers and water to allow normal growth. Many houseplant fertilisers contain trace elements. Trace-element deficiencies are more often caused by an extreme pH than by inadequate quantities in the soil. If a deficiency is suspected, foliar-spray with the trace element to remedy deficiencies. Our experience has been that trace-element deficiencies rarely occur indoors. We advise you not to add trace elements to indoor soils, which usually contain large amounts of trace elements already because of the addition of organic matter and liming compounds. It is easy to create toxic conditions by adding trace elements. Manufacturers also recommend using amounts of trace elements that may be too high for indoor gardens; so use them at about one-fourth of the manufacturer's recommended dose if an addition is found to be necessary.


Mn deficiency appears as chlorotic and the necrotic spots of leaf tissue between the veins. They generally appear on the younger leaves, although spots may appear over the whole plant. Manganese deficiencies are not common. Manganese is present in many all-purpose fertilisers. Mn deficiencies may occur if large amounts of Mg are present.


B deficiency may occasionally occur in outdoor soils. The symptoms appear first at the growing shoots, which die and turn brown or grey. The shoots may appear "burned," and if the condition occurs indoors, you might think the lights have burned the plant. A sure sign of boron deficiency is that, once the growing tip dies, the lateral buds will start to grow but will also die. B deficiency can be corrected by application of boric acid, which is sold as an eyewash in any drugstore. Use one-fourth teaspoon per quart of water. Recovery occurs in a few days with healthy growth of new shoots.


Mb deficiency occurs in outdoor soils, but rarely indoors. Mb is readily available at neutral or alkaline pH. Mb is essential for nitrogen metabolism in the plant, and symptoms can be masked for a while when N fertilisers are being used. Usually there is a yellowing of the leaves at the middle of the plant. Fertilising with nitrogen may remedy some of the yellowing. However, Mb symptoms generally progress to the growing shoots and new leaves often are distorted or twisted. Mb is included in many all-purpose fertilisers.


Zn-deficiency symptoms include chlorosis of leaf tissue between the veins. Chlorosis or white areas start at the leaf margins and tips. More definite symptoms are very small, new leaves which may also be twisted or curled radially. Zn deficiencies may occur in alkaline western soils. Galvanised nails can be buried or pushed into the stem. Commercial preparations of zinc are also available.


Cu deficiencies are rare; be careful not to confuse their symptoms with the symptoms of overfertilisation. The symptoms appear first on the younger leaves, which become necrotic at the tips and margins. Leaves will appear somewhat limp, and in extreme cases the whole plant will wilt. Treat by foliar-spraying with a commercial fungicide such as CuSO4.

Soilless Mixtures

Soilless mixtures are an alternative to using large quantities of soil. Their main advantage is complete control over the nutrients that your plants receive. Soilless mixtures are also inexpensive and easy to prepare. They have a near-neutral pH and require no pH adjustment.

Soilless mixtures are made from soil components such as vermiculite, sand, or perlite. Soilless mixtures should be blended in such a way that they hold adequate water, but also drain well and do not become soggy. A good general formula is two parts vermiculite to one part perlite. About 10 percent coarse sand or gravel can be added to give weight and stability to the pots. Instead of vermiculite, you can use Jiffy-Mix, Metro-Mix, Ortho-Mix, Pro-Mix and other commercial soilless mixtures, which are fortified with a small amount of necessary nutrients, including trace elements. You can also substitute coarse sand for perlite.


It is best to use solid containers with soilless mixtures rather than plastic bags. Grow the plants in one- to three-gallon containers. There won't be much difference in the size of the plants in one-gallon or in three-gallon sizes, but you will have to water a large plant every day in a one-gallon container. (The plants can always by transplanted to a larger container.) The pots must have drainage holes punched in the bottoms. Pot as usual, and add one tablespoon of dolomitic lime or two tablespoons of wood ash to each gallon of mixture.


Plants may have problems germinating in soilless mixtures. The top layer of mixture often dries rapidly, and sprouts may die or not germinate. Young seedlings also seem to have difficulty absorbing certain nutrients (notably potassium), even though adequate amounts of nutrients are being added. Since this difficulty may retard growth, it is best to start the plants in small pots with soil. Use eight-ounce paper cups, tin cans, or quart milk containers cut in half. Mix three parts topsoil or potting soil to one part soilless mixture. Fill the starting pots and germinate as usual. When the plants are two to three weeks old, transplant to the soilless mixture. First moisten the soil, and then remove the soil as intact as possible. You might handle the transplant like making castles, by carefully sliding the moist soil out of the pot. Or you can cut away the sides of the container while you place the transplant in the soilless mixture. When watering, make sure you water around the stem to encourage roots to grow into the soilless mixture.

Peat pellets that expand are also good for starting seedling. Plant several seeds in each pellet, and place it in the soilless mixture after the sprouts appear.


Soilless mixtures can be treated with a trace-element solution. We have grown crops with no special addition of trace elements, and the plants completed their lives without showing symptoms of trace-element deficiency. In these cases there were apparently enough trace elements in the lime and the fertilisers that were used to provide the major nutrients. Many all-purpose fertilisers also contain trace elements. However, it is a good idea to treat soilless mixtures with a mild solution of trace elements before planting. Large plants can be treated a second time during the third or fourth month of growth. Do not use trace elements more often unless plants show definite trace-element deficiencies.

Iron is the only trace element that is needed in more than minute quantities. Iron can be supplied by mixing a few brads or nails into the soilless mixture.

Use any soluble fertiliser that is complete, that is, that contains some of each of the major nutrients. Choose one with a formula that is highest in N but contains a good portion of both P and K. For example, Rapid-Gro is 23-19-17 and works well for soilless mixtures.

Table 18 gives a formula that has worked well for us. The figures in it are a guide for estimating the amounts of fertiliser to use. When choosing a fertiliser by means of this chart, use N for a guide. For example, suppose the only fertiliser you can find that has good proportions of the major nutrients as a 20-15-15. Divide 5 (the figure for N in the table) by 20 (the figure for N in the fertiliser), and get the result 1/4. That is, the fertiliser if four times as concentrated in N as you need; so you would use one-fourth the amount of fertiliser shown in Table 18. For instance, during the vegetative stage, you would give the plants one-half to three-fourths of a level teaspoon of fertiliser per gallon of water each time you water.

Table 18 – Guidelines for Fertilizing Soilless Mixtures Growth Stage N P2O5 K20 Amount Seedling 5 3 4 1.5 to 2 tsp/gal Vegetative 5 2 3 2 to 3 tsp/gal Flowering 5 5 3 0.5 tp 1.5 tsp/gal It is also not necessary to fertilise in these ratios. You could use a 10-10-10 fertiliser throughout growth; you would use half the amounts listed in Table 18. The most important point is that the plant receive enough of each element, not that they receive specific proportions.

Fertilising according to volume of fertiliser is not very accurate, and also does not take into account other variables (such as variety, light, temperature, etc.) that determine the amounts of nutrients your plants can use. However, it is a simple and useful way of estimating the plant's needs. You can more accurately gauge the plants' needs by giving a sample plant twice the concentration of fertiliser, and another half the concentration. Their performance will give you an idea of whether you are using too much or too little fertiliser. Too much fertiliser is the most damaging condition; so when in doubt give the plants less rather then more. Do not continue to give the plants the recommended amounts of fertiliser if the sample plant that is receiving less nutrients is growing as well as the other plants.

Another way of monitoring the plant's growth is to grow a few plants in a standard soil mixture. This will show you whether the plants in the soilless mixture are growing as fast as they should, and will give you a reference for diagnosing deficiencies.

Besides providing N, P, K, and the trace elements, you must also give your plants secondary nutrients. Ca is added by mixing a tablespoon of lime or two tablespoons of wood ash when preparing the soilless mixture. (Calcium is usually present in water and in many fertilisers as part of the salts that contain nutrients, for example, Ca(NO3)2.) Magnesium and sulfur are both found in common epsom salts, MgSO4. Use one-eighth teaspoon of epsom salts to each teaspoon of 5 percent N. For example, if you are using a 20 percent N fertiliser, you would use half a teaspoon of MgSO4 to each teaspoon of fertiliser. (Actually, enough sulfur is often present, either as part of the soilless mixture or as part of nutrient salts to allow growth.) Magnesium can also be supplied by using dolomitic limestone.

Soilless mixtures are something between soil mixtures and water cultures (hydroponics). With hydroponics, the plants are grown in a tank of water. The fertilisers are added in solution, and the water solution is periodically circulated by a pump.

Another variation on soilless mixtures is to add a small amount of soil or humus to the soilless mixture. Some examples are:

1. 4 parts soilless mixture to 1 part soil; 2. 8 parts soilless mixture to 1 part humus; 3. 15 parts soilless mixture to 1 part limed manure. Overfertilising is less a problem with soilless mixtures then with soil, because of higher concentrations of salts are tolerable in soilless mixtures and because excess salts are easily flushed out of the mixture. A good idea is to flush each pot once after two months of growth, again after four months. Any time the plants show symptoms of overfertilisation, leach the pots immediately. Flood each pot with plain water so that it runs out the drainage holes. Continue flooding the pots until a couple of gallons of water have run through the pot. Don't fertilise for at least a week. Then fertilise with a more dilute solution that was used before. {Figure 51a. Over fertilisation. Leaves turn bright gold and die, starting at the top of the plant.}

Posted – July 1st, 2010
under CannaLogic
Leave a comment
– go to post

Pots and Other Containers

In its natural state, marijuana may grow an extensive root system – a fibrous network of fine, lateral roots that branch off a main, carrot-shaped tap root. In dry areas, the tap root can grow more than six feet deep in its search for water. In moist areas with fertile soil (such as in potting mixtures), the lateral roots are able to supply water and nutritive needs and the tap root remains small, often only three or four inches long on a seven-foot-tall mature plant.

The purpose of the growing medium is to provide adequate water and nutrients in addition to anchoring the roots, which hold the plant upright. By watering and fertilising as needed, you could grow a six-foot plant in a four-inch ((Pots are measured by diameter across the top.)) pot or in a three-foot layer of soil over your whole garden; but neither of these extreme procedures is very practical.

Most growers use containers that will hold between two and five gallons of soil. These are a good compromise in terms of weight, space, cost, and labour. They can be moved easily and hold an adequate reservoir of water and nutrients to support a large mature plant.

Some growers use a single large box or several long troughs that hold a six- to 12-inch layer of soil. These have the advantage of minimal restriction of roots and less frequent waterings, but they require more soil and make rotating or moving the plants impractical.

Determine the right size pot to use in your garden by the amount of light per square foot. For a moderately lighted garden (15 to 25 watts per square foot and most window gardens), use one- to three-gallon containers. For gardens with more light energy – over 25 watts per square foot or one-half day or more of sunlight – use three- to eight-gallon containers. The smallest pot we recommend for a full-grown plant is eight inches or one gallon. This is also a good size for starting plants to be transplanted after two months.

Practically any container that can withstand repeated waterings and has a top at least as wide as its base will do. Each pot must have several holes in the bottom to assure drainage. Growers use flower pots, institutional-sized cans and plastic buckets, baskets and small trash cans, milk crates and wooden boxes.

Plastic trash bags are sometimes used when other large containers can't be found. They must be handled carefully, since shifting the soil damages the fragile lateral roots. They are also more difficult to work with when transplanting. However, a roll of trash bags is an available and inexpensive substitute for other large containers. Plastic bags should be double or triple bagged. Small holes should be punched in the bottom to drain excess water. Use masking tape to patch any unwanted tears. The capacity of the bag should be no more than twice as many gallons as the amount of soil used. For example, with four gallons of soil, the bag should be of a five-gallon, but not more than eight-gallon size. Otherwise, it will not form a cylinder, and the bag will remain a shapeless mass.

Use as many pots as can fit in the lighted area to make the most efficient use of space. Many growers prefer to start the plants in smaller pots, transplanting into larger pots when the plants are larger. There are definite advantages to this method in terms of the yield in the garden, given its space and light energy. Seedlings and small plants take up much les space than they will at maturity, so they can be placed closer together. As the plants grow and begin to crowd each other, remove the less vigorous (to smoke, of course) and transplant the rest into larger pots. Start plants which will be transplanted later in four- to eight-inch flower pots, or one-quart to one-gallon tin cans or milk containers. Peat pots or planting pots are made of compressed plant fibre for the purpose of starting young plants. They are available at garden shops and come in several sizes. Use at least a four-inch pot so that the roots are not restricted in early growth. Peat pots are supposed to break down in the soil, but marijuana's delicate lateral roots may not be able to penetrate unless you score or break away the sides while transplanting. Wax paper cup (six to eight ounces), filled with a soil mixture, work as well as peat pots and are cheaper.

BOX C Finding Large Containers Use your ingenuity in finding large containers. Large clay flower pots do not work any better than the large metal and plastic containers discarded by restaurants and food stores. Various milk containers are good starting pots. Many garden shops sell used pots for a few cents each. Wholesalers sell plastic pots by the carton at a discount. Large plastic pots and pails can sometimes be picked up inexpensively at flea markets or variety stores. Any vessel that holds an adequate amount of soil and does not disintegrate from repeated waterings is a satisfactory container.

Properties of Soil

The soil or growing medium serves as a source and reservoir for water, air, and nutrients, and to anchor the roots. Since marijuana grows extremely fast, it has higher water and nutritive needs than most plants grown indoors. The success of your garden depends on supplying the plant with a medium that meets its needs without creating toxic conditions in the process.

There is no such thing as the perfect soil for Cannabis. Each variety can grow within a range of soil conditions. For healthy, full, growth, marijuana prefers a medium with good drainage, high in available nutrients, and near a neutral pH (7.0). These conditions result from a complex set of physical, chemical and biological factors. We will refer to them simply as: (1) texture; (2) nutrients; (3) pH.

Most indoor growers prepare the growing medium using commercial potting mixes. These mixes are usually sterilised or pasteurised and have good general soil properties. Since they seldom list the contents, nutrients, or pH, do some simple test of your basic soil whether you buy or dig for it. Then you can adjust the soil to meet the basic requirements of the plant.


The texture of the medium determines its water-holding and draining properties. Marijuana must have a well-drained medium for healthy growth. Soils that hold too much water or hold it unevenly can drown the roots, leading to poor growth or death of the plant. In a well-drained soil the roots are in contact with air as well as water. Soils that have too much clay, or are overly rich in compost or other organic matter, tend to hold too much water and not enough air. This condition worsens in time. This is especially true of the soil in pots.

You can determine the texture of your soil from its appearance and feel. Dry soil should never cake or form crusts. Dry or slightly moist soil that feels light-weight, airy, or spongy when squeezed, and has a lot of fibrous material, will hold a lot of water. Mix it with materials which decrease its water-holding capacity, such as sand, perlite, or even kitty litter.

Wet soil should remain spongy or loose and never sticky. A wetted ball of soil should crumble or separate easily when poked.

Soil that feels heavy and looks dense with fine particulate matter, or is sandy or gritty, will benefit by being loosened and lightened with fibrous materials such as vermiculite, Jiffy Mix, or sometimes sphagnum moss.

Soil Conditioners to Improve Texture

Perlite (expanded sand or volcanic glass) is a practically weightless horticultural substitute for sand. Sand and perlite contribute no nutrients of their own and are near neutral in pH. They hold water, air, and nutrients from the medium on their irregular surfaces and are particularly good at aerating the soil.

Vermiculture (a micaceous material) and sphagnum moss contribute small amounts of their own nutrients and are near neutral in pH. They hold water, air, and nutrients in their fibre and improve the texture of sandy or fast-draining soils. Jiffy Mix, Ortho Mix, or similar mixes are made of ground vermiculite and sphagnum moss, and are fortified with a small amount of all the necessary nutrients. They are available at neutral pH, are good soil conditioners, and are also useful for germinating seeds.

Sphagnum and Peat Moss (certain fibrous plant matter) are sometimes used by growers to improve water holding and texture. Both work well in small amounts (10 to 15 percent of soil mixture). In excess, they tend to make the medium too acidic after a few months of watering. Use vermiculite or Jiffy Mix in preference to sphagnum or peat moss.


Nutrients are essential minerals necessary for plant growth. The major nutrients are nitrogen (N), phosphorus (P), and potassium (K), which correspond to the three numbers, in that order, the appear on fertiliser and manure packages, and that give the percentage of each nutrient in the mix (see section 9).

Marijuana prefers a medium that is high in nitrogen, and mid-range in phosphorus and potassium. Generally, the darker the soil, the more available nutrients it contains. Commercial soils usually contain a good balance of all nutrients and will support healthy growth for a month or two, even in smaller (one gallon) containers. Many growers prefer to enrich their soil by adding sterilised manures, composts, or humus. All of these provide a good balance of the three major nutrients. They also retain water in their fibre. In excess they cause drainage problems, make the medium too acidic, and attract insects and other pests. A good mixture is one part compost or manure to five to eight parts of soil medium. In large pots (four or five gallons), these mixtures might provide all the nutrients the plant will ever need. {Table 13.}

The many prepared organic and chemical fertilisers that can be mixed with the soil vary considerably in available nutrients and concentrations. Used in small amounts, they do not appreciably effect the soil texture. Many prepared fertilisers are deficient in one or more of the major nutrients (see Table 14). Mix them together so there is some of each nutrient, or use them with manures, which are complete (contain some of all three major nutrients). When adding fertilisers, remember that organic materials break down at different rates. It is better to use combinations which complement each other, such as poultry manure and cow manure, than to use either fertiliser alone. (See Table 22 in section 13 for a complete list of organic fertilisers.

Table 14 – Prepared Organic Fertilisers Type of Percentage by weight of Availability to fertiliser N P2O5 K20 Plant —————————————————————– Blood meal 13 0 0 Rapid/medium Bone meal 0.5 15 0 Medium/slow Blood/bone meal 6 7 0 Medium/slow Cottonseed meal 6 2 1 Slow/medium Fish meal 8 2 0 Slow/medium Hoof and bone meal 10 2 0 Slow Rock phosphate 6 24 0 Slow Wood ash 0 1.5 3-7 Rapid Greensand 0 0 2-8 Medium/slow Chemical fertilisers are made in about every conceivable combination and concentration. Pick one that is complete and where the first number (N) is at least equal if not higher than both P and K. For example, rose foods may be 12-12-12 or 20-20-20, and work very well for marijuana. Others are: Vigoro 18-4-5 and Ortho 12-6-6. The higher the number, the more concentrated the mix is, and consequently, the more nutrients are available.

Don't use fertilisers which come in pellets or capsules, or that are labelled "timed" or "slow release." They do not work as well indoors as do standard organic and chemical fertilisers. Chemical fertilisers seldom list the amount to mix per pot. You can get some idea by the instructions for application per square foot. Use that amount of each one-half cubic foot of soil mixture.

Many growers add no nutrients at this time but rely on watering with soluble fertilisers when they water. These fertilisers and their application are discussed in section 9.


The pH is a convenient measure of the acidity or alkalinity of the soil medium. It is another way of expressing whether the soil is bitter (alkaline) or sour (acid). The pH is measured on a scale of 0 to 14, with 7.0 assigned neutral; below 7.0 is acid and above is alkaline.

You can think of the pH as a measure of the overall chemical charge of the medium. It affects whether nutrients dissolve to forms available to the plant or to forms the plant can't absorb, remaining locked in the soil medium.

Marijuana responds best to a neutral (7.0 pH) medium, although in a fertile, well-drained soil, it will grow well in a range of 6.0 to 8.5. The simplest way to check the pH is with a soil-test kit from a garden shop or nursery. Test kits are chemicals or treated papers – for example, litmus papers or Nitrazine tape – that change colour when mixed with a wet soil sample. The colour is then matched to a colour chart listing the corresponding pH. Nitrazine tape is available, inexpensively, in drug stores. Some meters measure pH, but these are expensive. Agricultural agents, agricultural schools, and local offices of Cooperative Extension will test a soil sample for pH and nutrient content. Occasionally, a garden-shop person will check pH for you or will know the pH of the soils they sell.

Highly alkaline soils are characteristically poor soils that form cakes, crusts, and hardpan. Soil manufacturers don't use them, nor should they be dug for indoor gardens. Alkaline soils are treated with sulphur compounds (e.g., iron sulphate) to lower the pH.

We have never seen commercial soils that were too alkaline for healthy growth, but they are sometimes too acidic. The pH of acid soil is raised by adding lime (calcium-containing) compounds. Liming compounds come in many forms and grades. Some are hydrated lime, limestone, marl, or oyster shells, graded by their particle size or fineness. Use the finest grade available, since it will have more of a neutralising potential than a coarse grade. You need to use less and are more interested in immediate results than long-term soil improvement. For indoor gardens, use hydrated lime (available in any hardware store) or wood ashes to raise the pH. Hydrated lime is rated over 90 percent for its neutralising potential. Wood ashes will neutralise soil acids roughly one-half as well as hydrated lime. However, they also contain some nutrients (potassium, phosphorus, magnesium, and micronutrients) and are handy and free.

There is no exact formula we can give you for raising the pH. The pH does not have to be exact; it's and approximation. At low pH it takes less lime to raise the pH one point than it does when the pH is near neutral. Sandy soils need less lime to raise the pH one point than soils high in clay or organic matter. In general, add three cups of hydrated lime or six cups of fine wood ash to every bag (50 pounds or a cubic foot) of soil to raise the pH one point. For soils that test slightly acid (about 6.5), add two cups of lime or four cups of wood ash.

Soil that tested below 6.0 should be retested in about two weeks, after thoroughly mixing and wetting the soil. Repeat the application until the pH is in an acceptable range. Check the pH of plain water to see if it is influencing the tests. Distilled water is neutral, but tap water sometimes has minerals that can change the pH. Hard water is alkaline. Sulphurous water and highly chlorinated water are acidic.

If you have already added lime to a soil that now tests from 6.5 to 7.0, don't add more lime trying to reach exactly 7.0. Too much lime will interfere with nutrient uptake, notably of potassium, phosphorus, and magnesium.

General Soil Characteristics

The texture, pH, and available nutrients of the soil are all related. The most important single factor is texture (good drainage). When soil drains poorly, it creates anaerobic (without air) pockets in the soil. Bacteria or microbes that live without air will begin to multiply and displace beneficial microbes that need air to survive. The anaerobic microbes break down organic matter to a finer consistency, and release CO2 and organic acids to the medium. Drainage worsens, the acids lower the pH, and nutrients, even though present, become unavailable to the plant.

The result can be a four-month-old marijuana plant that is only three inches tall, especially if you use high concentrations of manures and composts, peat and sphagnum moss. If your soil lists manures or composts as additives, add no more than 10 percent of these on your own.f

Drainage problems sometimes develop after several months of healthy growth. It is a good idea to add about 20 percent sand or perlite to even a well-drained soil. You can never add too much of these; they con only improve drainage. They dilute the nutritive value of the soil, but you can always water with soluble fertilisers.

Mixtures using many components in combination seem to work particularly well. This may be because, at a micro-level each component presents a slightly different set of physical, chemical and biological factors. What the plant can't take up at one point may be readily available at another.

Preparing Commercial Soils and Mixes Garden soils (or loams) and potting mixes are actually two different groups of products, although they are frequently mislabelled. Some companies sell soil in large bags and a potting mixture in smaller bags, while labelling them the same. Soils and potting mixtures are usually manufactured locally, since transportation costs are prohibitive; so they differ in each area.


Texture and Nutrients

Soils and loams are usually topsoil blended with humus or compost for use as a top dressing in gardens, for planting large outdoor containers, or for the soil part of a potting mixture. They may have a tendency to compact under indoor conditions and will benefit from the addition of perlite or vermiculite. Soils and loams usually contain a good supply of nutrients and may support a full-grown plant in a large container. Commercial soils that are heavy generally work better than lightweight soils. Heavy soils usually contain topsoil, in which marijuana grows very well. Lightness indicates more fibrous content.

For example of possible soil mixtures, see Box D. pre?

BOX D Examples of Soil Mixtures* 1. 5 parts soil 2. 8 parts soil 2 parts perlite 3 parts sand 1 part cow manure 1/4 part 10-10-10 chemical fertiliser 3. 5 parts soil 4. 4 parts soil 2 parts perlite 1 part sand 2 parts humus 1 part vermiculite 1/2 part cottonseed meal 2 parts humus 1/2 part poultry manure 5. 3 parts soil 6. 6 parts soil 1 part perlite 2 parts perlite 1 part sand 2 parts vermiculite 2 parts Jiffy Mix 1/2 part poultry manure 1/2 part blood/bone meal 1/2 part cow manure 1/2 part wood ash 1 part wood ash *Almost all fertilisers are acidic, and need to be neutralised by lime. For the above mixtures, or any similar ones, mix in one cup of lime for each five pounds of manure, cottonseed meal, or chemical fertiliser in order to adjust the pH.

Potting mixes are intended to support an average-size house plant in a relatively small pot. They are sometimes manufactured entirely from wood and bark fibre, composts, and soil conditioners. These mixes are made to hold a lot of water and slowly release nutrients over a period of time, which is what most house plants require. For marijuana, these mixes seldom contain enough nutrients to support healthy growth for more than a couple of months. (Their N is usually low, P adequate, and K usually very high.) They work best when sand or perlite is added to improve drainage, and fertilisers are added to offset their low nutrient content.

The pH

Most commercial mixes and soils are between 6.0 and 7.0 in pH, a healthy range for marijuana. If you buy your soil, it will not be too alkaline for healthy growth, but it might be too acidic. You can minimise the chances of getting and acid soil by avoiding soils with "peat" or "sphagnum" in their names. Avoid soils that are prescribed for acid-loving plants such as African violets or azaleas, or for use in terrariums. With common sense, you can buy a soil, add two cups of lime to each large bag, and not have to worry about the pH. However, the surest procedure is to test the pH yourself.

Probably the best way to find the right soil for your garden is to ask long-term growers. They can relate their past experiences with various mixes and blends. Most long-term growers with whom we have talked have tried many of the mixes available in their areas. A reliable, enlightened nurseryperson or plant-shop operator may also be able to give you some advice.


Buying Soil Components



All the materials discussed here are available at farm and garden stores or nurseries. Many suburban supermarkets sell large bags of soil and humus. Always buy your materials in the largest units possible to reduce the cost.

Large bags of soil and humus come in either 50-pound bags or one- to four-cubic-foot bags. A 50-pound bag fills about six gallons. There are eight gallons to a cubic foot. Perlite is sold in four-cubic-foot bags (thirty-two gallons). Jiffy Mix and vermiculite are sold in four-cubic-foot bags and in 16 pound bags (about 18 gallons). Sand, perlite and vermiculite come in coarse, medium, and fine grades. All grades work well, but if you have a choice, choose coarse. Sand (not beach sand) is an excellent soil conditioner. The only disadvantage is its heavy weight. Buy sand from lumber yards or hardware stores where it is sold for cement work. It will cost from 1/50 to one-half the cost of garden or horticultural sand. Sand from piles at construction sites works very well.

Calculating the Amount of Soil

The maximum amount of soil mixture for any garden can be found by multiplying the capacity of the largest pot you plan to use by the number of pots that you can fit in the garden. In many cases, the actual amount of the mixture used will be somewhat less. Two illustrations follow.

1. A small garden with a two-tube, eight-foot fixture (160W). Using 20 watts per square foot for fast growth gives 160W divided by 20W/sq.ft. + eight sq.ft. The largest pot needed for this system is three gallons, but two gallons would work. You can fit about 10 three gallon pots in eight square feet; so 3 * 10 + 30 gallons of soil mixture are needed (see Box E).

BOX E Examples Showing How Much Soil Material to Buy to Fill a Known Number of Unit-Volume Containers Example 1. For a garden eight square feet in size, Buy Component Which amounts to 3 50-lb (6 gal. ea. ) bags of soil 18 gallons 1 cubic foot of perlite 8 gallons 30 lbs of humus 3 gallons 10 lbs of chicken manure 2 gallons TOTAL 31 gallons Example 2. For a garden 24 square feet in size, Buy Component Which amounts to 4 1-cu. ft. bags of soil 32 gallons 2 1-cu. ft. bags of perlite 16 gallons 1 1-cu. ft. bag of vermiculite 8 gallons 20 pounds of cow manure 3 gallons cottonseed meal 2 gallons wood ash 2 gallons TOTAL 63 gallons 2. A large garden with two two-tube, eight-foot VHO fixtures (four times 215 watts or 860 total watts) illuminating a garden three by eight feet, or 24 square feet.

860 watts divided by 24 sq. ft. = about 36W/sq. ft.

The largest pot size for this system is about five gallons. About 16 five-gallon containers can fit in 24 square feet; so 16 * 5 + 80 gal. of mixture are needed. But you could start many more plants in smaller containers and transplant when they are root-bound. You do not use more soil by starting in smaller pots, since all soil is reused. In many cases, you actually use much less soil.

In this system you could start and fit about 40 plants in one-gallon pots in 24 square feet. When the plants begin to crowd each other, some are harvested, making room fir the others, which are transplanted to larger pots. In practice, a high-energy system such as this one (36W/sq. ft.) will grow large plants whose size is limited mainly by the space available. Twelve large female plants are about the most you would want in the system during flowering and for final harvest. Sixty gallons of mixture is all that is needed for the seedlings and the mature crop. This is one-fourth les than the original estimate of 80 gallons, and you actually will harvest a lot more grass (see Box E).

Mixing and Potting

Mix your soil in a large basin, barrel, or bathtub. Individual pots are filled with mixtures by using a smaller container to measure out by part or volume.

Perlite, sand, and dry soil can give off clouds of dust. When mixing large amounts of these, wear a breathing mask or handkerchief over your nose and mouth.

To pot any of the mixtures, first cover any large drainage holes with a square of window screen or newspaper to prevent the mixture from running out. Place a layer of sand, perlite, or gravel about one inch deep to insure drainage. Fill the pots with soil mixture to within three-fourths of an inch from the top of the pot. If your mixture contains manures or composts, cover the last inch or two in each pot with the mixture minus the manure and compost. This will prevent flies, gnats, moulds, and other pests from being attracted to the garden. Press spongy soils firmly (not tightly) to allow for more soil in each pot; otherwise, after a period of watering, the soil will settle and the pot will no longer be full.

Some growers add a few brads or nails to each pot to supply the plant with iron, one of the necessary nutrients. Water the pots and allow them to stand for a day or two before planting. As the soil becomes evenly moist, beneficial bacteria begin to grow and nutrients start to dissolve. {Figure 40.}

Digging Soil

Most growers prefer to buy their soil, while some prefer to dig it. Marijuana cannot tolerate heavy clays, mucks, or soils that dry to crusts. Choose a soil from a healthy garden or field, or from an area that supports a lush growth of annual weeds.

Fields that support a good crop of alfalfa, corn or other grains will support a good crop of marijuana. Fields with beets, carrots, and sugar cane indicate a well-drained soil, with near neutral pH. Red clover, sweet clover, and bluegrass have soil requirements similar to those of marijuana. Garden soils are usually fertile and well-drained, but often need lime to counteract soil acidity.

Take the topsoil layer that starts about two inches below the surface debris. Good soil will look dark, feel moist, and small clean and earthy. Use all of the topsoil layer that maintains its dark colour and is interlaced with roots. Your hands should be able to easily penetrate the underlying topsoil if the soil is in good condition. When the soil changes colour, or roots no longer apparent, then you are past the fertile topsoil layer. Abundant worm, millipedes, and other small lifeforms are a good indication that the soil is healthy. A rich layer of topsoil collects by walls, fences, and hedges where leaves and debris collect and decay to a rich humus. Sift the soil to remove stones and root clods. Also, shake out the root clods, which are rich in nutrients.

Soil that is dug should be tested the same way as already prescribed. It should be adjusted with at least 30 percent sand or perlite (vermiculite for very sandy soils), since potting will affect the drainage of even well-drained soils. Never use manures or composts that are not completely degraded to a clean-smelling humus.

Soil that is dug must be sterilised to kill weed seeds, insect eggs, and harmful moulds and fungi. Some chemical treatments (e.g. formaldehyde) are mixed with water and poured over the soil to sterilise it. Soil can be sterilised in a pressure cooker at 15 pounds pressure for 15 minutes, or by baking wet soil in a large pot at 200 degrees for 30 to 40 minutes. Be advised that baking soil will release some formidable odours.

Growing Methods As we said before, there are probably as many growing methods as there are marijuana growers. These methods are personal preferences or adaptions to fit particular situations; one method is not necessarily better than any other. However, the value of a garden is often based on the amount of high-quality grass it yields. Since indoor gardens are limited in size, you want the plants to quickly fill the garden with lush growth in order to use the garden efficiently. Otherwise, for the first couple of months, the lights are shining on empty space.


Secondly, the possession of small quantities of marijuana will probably be decriminalised nationally within the next few years. Decriminalisation for personal possession will open the way for decriminalisation for cultivation for personal possession. But small quantities are more difficult to define for cultivation than for simple possession, which is done by weight. Several possible ways to limit the amount for cultivation have been raised: by the number of plants, by the area cultivated, or by the number of plants at a particular stage of development. The outcome may determine whether you try to grow the largest plants possible or the most plants possible in a given area.

There are several ways to increase your garden's yield.

1. Pinch or cut back the growing shoots when the plants are young. This forces each plant to develop several strong growing shoots and generally yield large robust plants. 2. Plant a number of plant in each pot. 3. Start many plants in small pots and transplant the best plants to larger pots when the plants crowd each other. 4. Use different light systems to grow plants at different growth stages. Here are some examples of how to carry out each of these four methods.

1. Fill the growing area with large containers (about five gallons each). Start several plants in each pot but thin the seedlings over a period of six weeks to two months, until one plant is left in each pot. During the fourth or fifth week of growth, pinch back the plants to about equal heights. Cut the growing shoot at about the fourth internode. Each plant will develop a sturdy stem which will support four to eight growing stems and will quickly fill any empty space in the garden. The whole garden is the treated like a hedge. After another month or two, you cut back the growing shoots again to have plants of equal heights. Remove the male plants as soon as they begin to release pollen (or before any male flowers open for sinsemilla). This will leave more space and light for the females to develop. By the time females flower, they've been cut back two or three times or more, and form a dense growth of growing shoots that fill the garden with a cubic layer of flowers. Some growers maintain the plants for up to a year before the final harvest.

{Figure 41. Plant clipped at fourth internode.}

2. This method also requires large pots. Instead of thinning the seedlings to leave one per pot, leave at least three. After a few months of growth, remove any plants that lag far behind or any plants that show male flowers. The value of this method is that the odds are at least seven to one that any pot will have at least one female plant.

Most of the plants you'll grow will fill out with branches by four months at the latest. Often the branches develop young seedlings. The plants may begin to look like small Christmas trees by the second to third months of growth.

Generally, you don't want to have more than three or four plants in a five-gallon container, because growth will be limited by competition for light and space.

{Figure 42. Basement growing factory in Atlanta.}

Some varieties never do fill out. The branches remain small, only two to three inches long, and yield very little grass. We've seen plants like this grown from grass from Vietnam, Thailand, Afghanistan, and Africa. These plants are also quite short, being four to six feet tall fully grown. With varieties like this, it is better not to pinch tops, and to start about six plants per square foot of garden space. At harvest, the garden will be crowded with top stems that are laden with flower clusters.

Of course, you don't know what varieties will look like until you've seen them grow. For most varieties, each plant will need at least one square foot or space at maturity. It is much less common to find varieties that naturally grow small or especially thin, and, therefore, are those of which you would want to plant more than a few per large pot.

3. Another popular way to grow is to start plants in a large number of small pots. As the plants crowd each other, some are removed and the rest transplanted to larger pots.

4. To get the most for your investment requires conservation of light and soil. When the plants are young, a large number fit into a small place. Some growers take advantage of this fact by having several light systems, each with plants at different growth stages. The plants are rotated into larger gardens and pots. This method conserves space, materials, and electricity, and yields a harvest every two months. Using this method, "growing factories" turn out a steady supply of potent grass. {Table 15.}

– go to post

What are the Benefits of Aerated Compost Teas vs. Classic Teas?

Aerated compost teas are the latest in scientific organic research today. In many ways, aerated teas offer greater immediate benefits than classic compost, manure, or other homemade foliar teas. Just by applying a cheap aquarium air pump to a 5 gallon bucket of tea, you can get amazing results. (Cheap, inexpensive aquarium airstones are also recommended to be applied to the hose in the water. This produces a better distribution of smaller air bubbles to make the aerobic soil/comosting microbes breed better.) Instead of just brewing teas for quick valuable water soluble nutrients from the compost or manure, you can breed a larger population of beneficial aerobic bacteria and fungi in the tea. It is the microherd in our soil, compost, and teas, that is really more important in soil development and disease control than just the soluble nutrients. Aerobic microherd populations reduce offensive smells in compost piles, the compost teas, and the soil. Aerobic microherd also break down bad poisons and pathogens into safe nutrients in hot compost piles and aerated compost teas. Diluted anaerobic compost or manure teas are great liquid fertilizers and disease controllers also. Many people prefer the anaerobic teas better because they are simpler and easier to design and apply. However, recent research has proven that the aerobic microherd populations fight diseases and bad soil and plant pathogens better and supply more power to your soil's total health and texture. Keep in mind that all types of organic and natural foliar teas are designed to complement and enhance, not replace, basic composting, green manuring, and organic mulching techinques in your garden. The soil microherd continue over months and years to eat up insoluble OM in the existing soil and the extra soil amendments and break them down into more available soluble nutrients for plants later in the year.

Technically even in un-aerated teas there is still some aerobic action taking place for several days. All fungi is aerobic. Some bacteria are totally aerobic, some bacteria are totally anaerobic, and some bacteria can act both aerobic or anerobic based on the soil or tea environment. Un-aerated teas can continue to keep alive some aerobic or aerobic/anaerobic microbes, for up to 10 days in a watery solution. After 10 days, the whole un-aerated tea will contain only anerobic microbes.

You can expect different microbial population levels in your tea based on weather, climate, temperature, seasons, etc. In the summertime you can expect your teas to brew faster and get to your optimal microbial levels faster than in cooler fall weather. Also tea odors, color, and foaminess on top of the tea, will vary based on temperatures too.

************************************************** **********

There are several different levels of teas as well as different recipes and styles. Here is the simple steps as outlined by one of our own GardwenWeb members who is an expert on teas and compost. This is a brief description of the different strength levels of tea making as outlined by "BILL_G" :

Level 1: Put a shovel full of good compost in a 5 gallon bucket of water, wait one week, and apply to garden or lawn either full strength or up to a 1:4 water ratio. This is an excellent source of ready available soluble nutrients. NOTE: If you stir your brew daily or every other day, it helps get more oxygen to the mix for better decomposition and better aerobic microbial population growth.

Level 2 : Do same as above, but now add to the recipe a few cups of alfalfa pellets or some other cattle feed. Now you have extra nitrogen and trace elements from the bacterial foods.

Level 3: Do all above plus now add the air pump bubbler. Now you have more aerobic microbes to add to your soluble nutrients in the tea.

Level 4 : Do all the above and now add a few tblsp of molasses or other simple sugar products. Now you really maximize the aerobic microbes in the tea, which in turn produce even more extra soluble nutrients from the bacterial foods.

************************************************** ********

Here is my suggestions also. You can add more high nitrogen foods in the tea. Remember the only main ingredients that are necessary to make a good bacterial and soluble nutrients tea are: aerobic compost and sugar products. Everything else is optional. Your teas can be as creative as you are. Let's assume a 5 gallon tea recipe for our example:

1. Add 1/2 bucket of finished hot compost. This supplies most of the beneficial aerobic microbes and soluble nutrients. Some people use slightly immature aerobic compost because it has more fresh nitrogen in it, but less microbes than finished hot compost.

2. Use 2-3 tblsp molasses, brown sugar, or corn syrup. This feeds and breeds the aerobic bacteria. Sugar products are mostly carbon which is what the microherd eat quickly. Add about 1-2 more tblsp of molasses for every 3 days of aerobic brewing to make sure the sugar is digested before touching the soil at application time, and to guarantee that the aerobic bacteria population stays strong throughout the brewing process. Molasses also contains sulfur which is a mild natural fungicide. Molasses is also a great natural deodorizer for fishy teas. For a more fungal tea don't add too much simple sugar or molasses to your aerobic teas. Use more complex sugars, starches and carbohydrates like in seaweed, rotten fruit, soy sauce, or other fungal foods.

3. Add 1-2 cans of mackerel, sardines, or other canned fish. Supplied extra NPK, fish oil for beneficial fungi, calcium from fish bones. Most commercial fish emulsions contain no fish oils and little to no aerobic bacteria. Fresh fish parts can be used, but because of offensive odors, it should composted separately with browns like sawdust first before adding to the tea brew. NOTE: For those organic gardeners who prefer vegetarian soil amendments, you can skip the fishy ingredients, it's not necessary. There is plenty of NPK in alfalfa meal and other grains that you can use.

(NOTE: If you use canned fish products, you may want to let it decompose mixed with some finished compost, good garden soil, etc. in a separate closeable container for a few days before using. Since most canned meat products contain preservatives, this will guarantee that the good microbes in the tea will not be killed off or harmed in brew making.)

4. Add 1 pack fresh seaweed. Supplies all extra trace elements. Seaweed can contain about 60 trace elements and lots of plant growth hormones. Seaweed is a beneficial fungal food source for soil microbes. Liquifying the seaweed makes it dissolve even faster.

5. Add 1-2 cups of alfalfa meal, corn meal, cattle feed, horse feed, catfish or pond fish feed. Supplies extra proteins and bacteria. Corn meal is a natural fungicide and supplies food for beneficial fungi in the soil.

6. Add rotten fruit for extra fungal foods. Add green weeds to supply extra bacterial foods to the tea.

7. Good ole garden soil is an excellent free biostimulant. Garden soil is full of beneficial aerobic bacteria, fungi, and other great microbes. Some people make a great microbial tea just out of soil. Forest soil is usually higher in beneficial fungi than rich garden soil.

8. Fill the rest of the container with rainwater, compost tea, or plain de-chlorinated water to almost the top of bucket. You can make good "rain water" from tap water by adding a little Tang (citrus acid) to the water mix before brewing. Urine water is also an excellent organic nitrogen source for teas (up to 45% N).

9. Some people like to add 1-2 tblsp of apple cider vinegar to add about 30 extra trace minerals and to add the little acidicity that is present in commercial fish emulsions. Many fish emulsions contain up to 5% sulfuric acid to help it preserve on the shelf and add needed sulfur to the soil. You can add extra magnesium and sulfur by adding 1-2 tblsp of Epsom salt to the tea.

10. Apply the air pump to the tea. NOTE: Some organic tea brewers prefer not to use the air pump method. You can get some extra oxygen in the tea by stirring it daily or every other day. The air pump just makes the oxygen levels in the tea happen faster than by hand, thus greatly increasing the rate of aerobic microbial growth in the tea. If you prefer to use the air pump, let it bubble and brew for at least 1-3 days. (NOTE: The 3 days limit is just a good guideline. The real test of brewing time is by your own sight and smell test, because everybody's tea is different due to the various microbial species and breeding activity that takes place during the brewing process.) The aerobic tea is ready to use when it has either an earthy or "yeasty" smell or a foamy layer on top of the tea. If not satisfied with the look or the smell of the tea, go up to a week of brewing. The extra brewing time will help the microbes digest more of the insoluble bacterial and fungal foods in the tea and make it more available for your plant's or your soil's nutritional needs.

Apply this tea full strength to get full nutrient levels per plant, or dilute it from a 1:1 down to a 1:5 water ratio to spread the beneficial microbes over a 1-acre garden area (mix 5 gallons of tea per 25 gallons of rainwater).

To reduce straining, you can place all your ingredients in a closed panty hose or laundry bag during the brewing cycle (don't use a too fine mesh bag or the beneficial fungi can't flow properly through the bag).

Here's another method to avoid straining and to maximize the amount of microbes in application: Simply turn off the air pump, stir the entire mixture real hard, and then let the mixture sit still for about 30 minutes. Scoop off the top juice straight into a watering can for application.

You can apply with a watering can, or simple cup, or in a sprinkling system. All compost teas can be used as a foliar feed or soil drench around plants. They also make great compost pile nitrogen and bacterial activators to heat up the pile for faster finished composting. Always take the remains for teas and recycle them back into your compost piles.

As stated, you can use your homemade tea as a foliar feed or as a soil drench or both. Soil drenches are best for building up the soil microbial activities and supplying lots of beneficial soluble NPK to the plant's root system and the topsoil texture. Foliar feeds are best for quick fixes of trace elements and small portions of other soluble nutrients into the plant through its leaves. Foliar feeds are also good for plant disease control. Foliar feeds work best when used with soil drenches or with lots of organic mulches around plants. You can poke holes in the soil around crop roots with your spade fork, to get more oxygen in the soil to further increase organic matter decomposition and increase microbial activity in the soil.

Aerated teas can also be used to greatly speed up the decomposition process of hot compost piles. The extra aerobic microbes in the tea will breed and cooperate with the aerobic microbes in the organic matter in the compost pile.

You should not use any liquid soaps as a spreader-sticker agent in a fertilizing/biostimulant tea like this. It can hinder or harm your aerobic microbes that you just grew in the tea. You need to use better products in your tea like liquid molasses, dry molasses powder, fish oil, or yucca extract as a spreader-sticker.

A good aerated tea is very economical. 5 gallons can be diluted to biostimulate an entire acre of garden via foliar spraying only. If you soil drench only, it takes at least 15 gallons of tea, before diluting, to cover an acre of garden soil. Also there is enough aerobic bacteria and fungi in a good 5 gallon batch of aerated tea, that is the equivalent of about 10 tons or 40 cubic yards of regular compost!

These homemade aerated compost teas are just as powerful, maybe more powerful, than any commercial natural or organic fertilizer or soil amendment on the market today. And they are a lot cheaper too! So have fun, be creative, and keep on composting!

Happy Gardening!

– go to post

Growing marijuana indoors is fast becoming an American Pastime. The reasons are varied. With the increased interest and experimentation in house plant cultivation, it was inevitable that people would apply their knowledge of plant care to growing marijuana. Many of those who occasionally like to light up a joint may find it difficult to locate a source or are hesitant to deal with a perhaps unsavory element of society in procuring their grass. There is, of course, the criminal aspect of buying or selling grass; Growing marijuana is just as illegal as buying, selling, or smoking it, but growing is something you can do in the privacy of your own home without having to deal with someone you don't know or trust. The best reason for growing your own is the enjoyment you will get out of watching those tiny little seeds you picked out of you stash sprout and become some of the most lovely and lush of all house plants.

Anyone Can Do It

Even if you haven't had any prior experience with growing plants in you home, you can have a successful crop of marijuana by following the simple directions in this pamphlet. If you have had problems in the past with marijuana cultivation, you may find the solutions in the following chapters. Growing a marijuana plant involves four basic steps:

1. Get the seeds. If you don't already have some, you can ask your friends to save you seeds out of any good grass they may come across. You'll find that lots of people already have a seed collection of some sort and are willing to part with a few prime seeds in exchange for some of the finished product.

2. Germinate the seeds. You can simply drop a seed into moist soil, but by germinating the seeds first you can be sure that the seed will indeed produce a plant. To germinate seeds, place a group of them between about six moist paper towels, or in the pores of a moist sponge. Leave the towels or sponge moist but not soaking wet. Some seeds will germinate in 24 hours while others may take several days or even a week.

3. Plant the sprouts. As soon as a seed cracks open and begins to sprout, place it on some moist soil and sprinkle a little soil over the top of it.

4. Supply the plants with light. Flourescent lights are the best. Hang the lights with two inches of the soil and after the plants appear above the ground, continue to keep the lights with two inches of the plants. It is as easy as that. If you follow those four steps you will grow a marijuana plant. To ensure prime quality and the highest yield in the shortest time period, however, a few details are necessary.


Your prime concern, after choosing high quality seeds, is the soil. Use the best soil you can get. Scrimping on the soil doesn't pay off in the long run. If you use unsterilized soil you will almost certainly find parasites in it, probably after it is too late to transplant your marijuana. You can find excellent soil for sale at your local plant shop or nursery, K-Mart, Wal Mart, and even some grocery stores. The soil you use should have these properties for the best possible results:

1. It should drain well. That is, it should have some sand in it and also some sponge rock or pearlite.
2. The ph should be between 6.5 and 7.5 since marijuana does not do well in acidic soil. High acidity in soil encourages the plant to be predominantly male, an undesirable trait.
3. The soil should also contain humus for retaining moisture and nutrients.

If you want to make your own soil mixture, you can use this recipe: Mix two parts moss with one part sand and one part pearlite or sponge rock to each four gallons of soil. Test your soil for ph with litmus paper or with a soil testing kit available at most plant stores. To raise the ph of the soil, add 1/2 lb. lime to 1 cubic foot of soil to raise the ph one point. If you absolutely insist on using dirt you dug up from your driveway, you must sterilize it by baking it in your oven for about an hour at 250 degrees. Be sure to moisten it thoroughly first and also prepare yourself for a rapid evacuation of your kitchen because that hot soil is going to stink. Now add to the mixture about one tablespoon of fertilizer (like Rapid-Gro) per gallon gallon of soil and blend it in thoroughly. Better yet, just skip the whole process and spend a couple bucks on some soil.


After you have prepared your soil, you will have to come up with some kind of container to plant in. The container should be sterilized as well, especially if they have been used previously for growing other plants. The size of the container has a great deal to do with the rate of growth and overall size of the plant. You should plan on transplanting your plant not more than one time, since the process of transplanting can be a shock to the plant and it will have to undergo a recovery period in which growth is slowed or even stopped for a short while. The first container you use should be no larger than six inches in diameter and can be made of clay or plastic. To transplant, simply prepare the larger pot by filling it with soil and scooping out a little hole about the size of the smaller pot that the plant is in. Turn the plant upside down, pot and all, and tap the rim of the pot sharply on a counter or the edge of the sink. The soil and root ball should come out of the pot cleanly with the soil retaining the shape of the pot and with no disturbances to the root ball. Another method that can bypass the transplanting problem is using a Jiffy-Pot. Jiffy pots are made of compressed peat moss and can be planted right into moist soil where they decompose and allow the passage of the root system through their walls. The second container should have a volume of at least three gallons. Marijuana doesn't like to have its roots bound or cramped for space, so always be sure that the container you use will be deep enough for your plant's root system. It is very difficult to transplant a five-foot marijuana tree, so plan ahead. It is going to get bigger. The small plants should be ready to transplant into their permanent homes in about two weeks. Keep a close watch on them after the first week or so and avoid root binding at all costs since the plants never seem to do as well once they have been stunted by the cramping of their roots.


Marijuana likes lots of food, but you can do damage to the plants if you are too zealous. Some fertilizers can burn a plant and damage its roots if used in to high a concentration. Most commercial soil will have enough nutrients in it to sustain the plant for about three weeks of growth so you don't need to worry about feeding your plant until the end of the third week. The most important thing to remember is to introduce the fertilizer concentration to the plant gradually. Start with a fairly diluted fertilizer solution and gradually increase the dosage. There are several good marijuana fertilizers on the commercial market, two of which are Rapid-Gro and Eco-Grow. Rapid-Gro has had widespread use in marijuana cultivation and is available in most parts of the United States. Eco-Grow is also especially good for marijuana since it contains an ingredient that keeps the soil from becoming acid. Most fertilizers cause a ph change in the soil. Adding fertilizer to the soil almost always results in a more acidic ph.

As time goes on, the amount of salts produced by the breakdown of fertilizers in the soil causes the soil to become increasingly acidic and eventually the concentration of these salts in the soil will stunt the plant and cause browning out of the foliage. Also, as the plant gets older its roots become less effective in bringing food to the leaves. To avoid the accumulation of these salts in your soil and to ensure that your plant is getting all of the food it needs you can begin leaf feeding your plant at the age of about 1.5 months. Dissolve the fertilizer in worm water and spray the mixture directly onto the foliage. The leaves absorb the fertilizer into their veins. If you want to continue to put fertilizer into the soil as well as leaf feeding, be sure not to overdose your plants.

Remember to increase the amount of food your plant receives gradually. Marijuana seems to be able to take as much fertilizer as you want to give it as long as it is introduced over a period of time. During the first three months or so, fertilize your plants every few days. As the rate of foliage growth slows down in the plant's preparation for blooming and seed production, the fertilizer intake of the plant should be slowed down as well. Never fertilize the plant just before you are going to harvest it since the fertilizer will encourage foliage production and slow down resin production. A word here about the most organic of fertilizers: worm castings. As you may know, worms are raised commercially for sale to gardeners. The breeders put the worms in organic compost mixtures and while the worms are reproducing they eat the organic matter and expel some of the best marijuana food around. After the worms have eaten all the organic matter in the compost, they are removed and sold and the remains are then sold as worm castings. These castings are so rich that you can grow marijuana in straight worm castings. This isn't really necessary however, and it is somewhat impractical since the castings are very expensive. If you can afford them you can, however, blend them in with your soil and they will make a very good organic fertilizer.

Posted – July 1st, 2010
under CannaLogic
Leave a comment
– go to post

Maybe you're tired of paying top dollar for weed or you want to make some extra money, but where do you start? This guide assumes you have no prior knowledge whatsoever of growing marijuana. It is not intended to be a complete guide but rather an overview of everything you need to get started. The concept assumes you are growing indoor but some of the concepts can be applied to growing outdoors. If you have ever cared for a house plant you have most of the knowledge you already need to care for a marijuana plant. Marijuana like all plants require these simple things:

*Fresh Air


Marijuana like nearly every other plant starts is started from seed. The plant will sprout out and grow very vigorously to about 2' within 1-2 months. During this time the plant is exposed to 18 hours of light and 6 hours of darkness. This is known as the vegetative state because the plant is concentrating all of its energy into producing leaves, stems and roots. When the plant is about 2' tall the light cycle is changed to 12 hours of light and 12 hours of darkness. This is known as the flowering state because now the plant is concentrating all of its energy into producing buds. This stage lasts 4-12 weeks. After the flowering stage the plant is harvested and dried.


All plants require light and food for a process called photosynthesis. Photosynthesis is the process in green plants by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source. Photosynthesis release oxygen as a byproduct. Fortunately we only need very modest information about photosynthesis to be successful!

The best type of light for plants is always the sun. The sun is much more powerful than any artificial light. When growing indoors requires we use artificial light rather than the sun but fortunately it has some very important advantages:

*You have a lot more control over lighting cycles and can have multiple crops per year
*Unaffected by different seasons and weather conditions

If you are growing indoor and using artificial light you can never match the actual light output of the sun – therefore you want as much light output as possible. Standard incandescent bulbs (most commonly found in house lamps) are too inefficient at converting electricity into light output for growing cannabis. Although marijuana can be growing using fluorescent lights for best results a HID (High Intensity Discharge) lighting system is highly recommended. There is two types of HID lighting systems are are suitable for growth: HPS (High Pressure Sodium) and MH (Metal Halide). HPS systems are more efficient for the flowering stage and MH are more suitable for the vegetative stage.


Marijuana is a very fast and vigorously growing plant (they don't call it 'weed' for nothing). To ensure it is growing at its optimal potential it is important that you supply it with a constant supply of fertilizer. Fertilizer should be added to the plant about 2 weeks after it has sprouted from the seed and applied until 2 weeks before harvest. The last 2 weeks of harvest where only water and no fertilizer is added is called “flushing”. Flushing is done to remove the excess fertilizer from the plant and to improve its quality.

Fertilizer is such that “you get what you pay for”. Using low-cost generic fertilizers is discouraged in favor of using quality fertilizers designed specifically for growing cannabis. The amount and frequency to fertilizer your plant is specific to the individual type of fertilizer you use. Consult the instructions on the label for specific feeding instructions.

Fresh Air

In addition to light and food C02 is required for photosynthesis to take place. Within the air we breathe there is enough C02 for the plant. Plants through the process of photosynthesis use C02 and convert it into oxygen. If the air in the room is not constantly replaced with fresh air the plants will suffocate and not achieve optimum growth. Ventilation will also keep the grow room at the proper temperature (70-80° Fahrenheit) by cooling the room.

To achieve this your grow room must have some sort of ventilation system. Usually this is achieved with an INPUTOUTPUT ventilation channels. The air is moved via one or more fans. Input ventilation channel is fresh air that is usually taken from outside. No smell is transmitted from the input channel because air is being pulled in. Air is expended via the output channel. The output channel will also remove excess smell and heat generated from lights. and

The output must must take into account the odor produced by the plants. Odor is one of the most common ways grow ops get discovered. Fortunately there is several methods for dealing with the expended air. The first method is by deodorizing the air by using either a charcoal filter or ozone generator. It can then be safely vented back outside without raising suspicion of a grow op via odor. The second method is by venting the expended air to either the sewer system (by taking out the toilet) or through the bathroom or oven vents where it will go through the top of the building and up into the atmosphere (hot air rises).

– go to post

GROWING OUTDOORS Copyright 2002 by Jorge Cervantes

Tom, an American, is one of the most successful growers I have ever interviewed. His methods are extremely simple and easy. He is a smart, lazy man who pays attention to Mother Nature. Tom’s complete and simple understanding of plant growth makes him a very successful guerilla grower. These simple concepts are key to assimilating guerilla growing.

………..Wild marijuana plants are vigorous, aggressive, competitive weeds. Some varieties have a large root system which helps them survive moisture stress and poor soil. Plants spaced at least 10 feet apart will grow to a height of 3 – 5 feet in dry climates. Cannabis is a survivor. Given control of a growing area of 4 to 12 square feet, in poor soil, mature plants will grow to about 5 feet tall with a strong terminal main bud or cola. The yield is relatively heavy considering the amount of cultivation work. Add a little more effort during soil preparation and planting to grow several times more dope. Loosen the soil, amend it a little and throw in a handful of polymers*.

Cover the soil around the plant with a thick layer of natural mulch to attract condensed water and to keep soil moisture from evaporating. Just these simple measures may double the yield. *polymer crystals are small crystals that expand to about 15 times their size when moistened by water. They are added to soil to prolong time between watering.

Reasonable soil will grow a plant that is 7 – 8 feet tall with roots that spread 5 feet across and 6 feet deep. This plant will yield 2 – 10 times more marijuana than if planted in poor soil.

Polymer crystals hold water and gradually release it as the soil dries out. Polymer crystals cut watering frequency dramatically. To prepare an outdoor garden, remove the weeds in the fall, dig planting holes and prepare the soil. The soil will absorb rainfall and be well mixed the next spring. Cover each planting hole with a layer of mulch to protect it from winter rains and temperatures. This layer of mulch is very important. Do not leave soil bare all winter.

Transplant seedlings or clones in spring and grow marijuana plants as you would tomatoes. If growing in poor soil, give each plant a hole that is 4 feet deep and 4 feet in diameter and refill with your best compost/potting soil/planting mix. Break up the soil in a wide 6-foot radius, only 6 – 8 inches deep, because roots branch out. To water cheaply and effectively, cut a 3/16th hole in the bottom of a 5-gallon bucket. Mix an inexpensive all purpose water-soluble fertilizer with 5-gallons of water in the bucket and put the hole by the stem of the plant. Growing like this, only with 4 – 6 buckets of water will last all summer. Water with one bucket every 10 days during hot weather. Watering with this regimen, the plants will grow as well as if they had lots of water.

If plants receive no water, a small bud grows on top of plant. A 5 foot tall plant may produce from 1 – 6 ounces of smokable bud. This same plant, given just a little water, will grow much better and produce more high quality smoke.

Grow a plant that takes 20 – 40 gallons of supplemental water per growing season, or grow a plant that gets an infinite amount of water and achieve very near the same weight at harvest. Why?

First the plant must use all water in the soil. The plant must get all the nutrients it needs that naturally occur in the subsoil. If you slightly increase the water and nutrient supply, you get a much stronger and robust plant. How much water is there in the soil already?

Reasonable soil has one inch of water per foot of area. There are about 30 gallons of water already in the soil in 4 x 4 x 4-feet area of reasonable soil. Look for big green stands of vegetation. Kill green vegetation in the fall and grow the garden the following spring. One of the main things to look for is an adequate water supply. Many parts of the US and different parts of the world get rainfall in the summer growing season to support a dry land crop. The rainfall you need is from ¼ to 1 inch per week. It is very important that it rains regularly during the spring and summer months. Dry fall weather is the best for harvests. Heavy rains and high humidity will cause bud mold.


Site Preparation and Soil

Preparing three sites required three different strategies. The small greenhouse needs a little bit of heat to speed growth. Easy ways to warm a greenhouse include natural heat generated by the sun and artificial heat from electricity or burning fossil fuel. To conserve the natural heat from the sun, Vansterdan lined the bottom of the greenhouse with two inches of Styrofoam. He also placed a one- inch-thick lining six inches high around the bottom perimeter of the greenhouse. He constructed the greenhouse from Filon, a corrugated, translucent fiberglass. The low-slung greenhouse looks like a small storage area because you can’t see inside. Filon transmits enough light for vegetative growth even when low levels of natural sunlight are available. To add more heat, Vansterdan used duct tape to fasten heating cable to the Styrofoam floor and covered it with a thin piece of sheet metal to transmit the heat evenly.

Marijuana blends and is camouflaged by many different back yard plants. Look for plants with similar leaf shapes that grow fast.

Vansterdan is an avid vegetable gardener and has been adding manure and compost to the raised beds in his backyard garden for more than 10 years. His neighbors are used to his fanatic gardening and do not suspect him of growing marijuana. Every spring he spreads three cubic yards of finished compost and manure over the garden. He adds dolomite lime to raise and stabilize the acidic pH and rototills it into the soil. Once vegetables are planted and growing well,

Vansterdan transplants hardened-off clones into the garden plot. “The soil is so rich and fertile, I don’t even need a shovel to dig a planting hole. I just open the soil with my hand, put the clone in and press soil around the root ball before watering it in” said Vansterdan with the pride of a confirmed organic gardener.

Raised Beds

The soil in cool coastal regions is heavy clay that warms slowly and drains poorly. Raised beds turn both of these detriments into compliments. Beds need to be raised 6 – 8 inches to provide the benefits of warmth and improved drainage. Using raised beds, Vansterdan plants from two weeks to a month earlier than other gardeners. If poor drainage is the only obstacle and making raised beds too difficult because of a remote garden location, smart growers loosen clay soils with a pick and shovel before cultivating in granulated gypsum to break up clay soil.


The basics of composting are simple: collect organic matter: grass clippings, chopped up branches and vegetative matter, pile it up and let it rot. The pile must be at least one yard square to hold more heat than is dissipated. “It’s easy to make compost,” said Vansterdan. “In the summer, professional gardeners cut grass and other yard debris and haul it away. I asked one of them to dump the debris at the end of my driveway. He gives me about three cubic yards a week. By the end of the summer, I have more than 40 yards of grass clippings and garden debris. I mix it with wood chips to provide carbon and air. The following year, I have 3 to 6 cubic yards of the best compost in the world!”

“I know one hard core grower that plants spring crops on top of compost piles. He piles the compost up two or three feet high, making a raised bed. Next he throws 3 or 4 inches of good dirt on top and plants foot-tall clones, aye. By the time the roots penetrate down into the compost, it has cooled down and doesn’t burn. The compost keeps the clones warm and he puts a greenhouse on top to protect the foliage. If he’s lucky and the weather cooperates, he harvests a spring crop.” said Vansterdan with a bewildered grin.

Mountain and Bog Soil.

“Most of the soil around here is full of Douglas fir needles and is very acidic. The pH is around 5, which makes plants grow slowly, aye. I look for patches where pasture grass grows. The soil is normally a little poor, lacking nutrients, so I have two strategies. The first one, I use for low lying areas. To plant in marshy, grassy areas, I cut a square yard of moist sod from the ground with a shovel, turn it over, and plant in it. This way I can transplant about 50 clones in a day. The marshy ground supplies enough water and I just add a bit of time-release fertilizer when I transplant, aye. I add another handful of flowering time-release fertilizer when I go back and check them the first week in August. Sure, the plants don’t grow as big as the ones in my back yard, but I don’t work too hard, aye.”

To plant in marshy, grassy areas, this grower cuts a square yard of moist sod from the ground with a shovel, turns the entire piece over (180 degrees) and plants in it.

Vansterdan has been planting in the mountains for 12 years in secret gardens only accessible by foot or mountain bike. He harvests about half of the clones he plants. The rest are lost to humans and other animals, insects, fungus and weather. “Growing in BC is different than growing around Toronto, aye. The weather here on the Lower Mainland is mild in the summer, with occasional rain showers. The heavy rains start in September. If your crop isn’t out of the ground by the middle of September, the buds get wet and moldy, usually gray mold (botrytis), sometimes powdery mildew starts earlier on leaves. Toronto is in the middle of the continent and a lot hotter and more humid. Plants grow faster, but still need to be out of the ground before the frost,” said Vansterdan, with a strong Canadian accent.

If the weather coperates and Vansterdan plants early in the year, clones establish a dense root system and don’t need much water during the growing season. A heavy layer of mulch helps conserve water and combat weeds.

Hardening-off Cuttings and Seedlings

After clones have rooted in rockwool cubes for three weeks, Vansterdan transplants them into 4-inch pots full of organic soil mix. He handles root cubes carefully and waters transplants heavily so roots grow into the new soil. He leaves the cuttings under a 400- watt HP sodium lamp for two weeks before moving them outdoors to harden-off in the greenhouse. He keeps clones in trays (nursery flats) so they are easy to handle. Since there is not enough room for all of the transplanted clones in the greenhouse, Vansterdan fills the greenhouse three different times. The first crop of clones is transplanted into the soil or 3-gallon pots and set out in the back yard garden after they have hardened-off for two or three weeks. The second crop of clones is moved in to harden-off and later transplanted to the local mountain plots. The third set of clones is moved into the greenhouse and grown until they are about 18 inches tall before he prompts flowering. Vansterdan covers the greenhouse to induce flowering with 12 hours of darkness.

Transplanting to the Mountain Site

The clones he transplants to the mountain site are grown in a tall container to promote a strong deep root system. The containers Vansterdan uses to clone the plants in are 6 inches tall and 3 inches square.

“I learned this trick when I worked for the Forrest Service, aye,” explained Vansterdan, “They grow tree seedlings in tall containers so they will have a deep strong root system. The deep, dense root system makes a strong plant, aye. I won’t be able to water or give much care to these babies. A strong root system makes up for the lack of care”.

Clones in tall containers with a deep root system have the best chance of survival in remote, low maintenance gardens. A clone buried deep in ground will grow roots along the stem in a few weeks. Planting the root ball a few inches deeper makes plants easier to maintain.

Other growers transplant foot-tall clones with smaller root systems. They remove the first few sets of leaves and bury the root ball deeper in the ground, leaving only six inches of foliage above ground. The clone will grow roots along the underground stem in the next few weeks.

“I try to go back and check on the clones two or three times after I plant them. Every time I go back there I pee around the plants to scare the deer and rabbits away. I also save urine in a bottle and sprinkle it around them, because I run out,” said Vansterdan with a grin.

Seed Germination and Care

Cannabis seeds need only water, heat and air to germinate. Seeds, without light, properly watered, will germinate in 2 – 10 days, in temperatures from 70 – 90 degrees F. Germination is faster at higher temperatures but declines if temperatures climb above 90 degrees F. When the seed germinates, the outside protective shell splits and a tiny, white sprout (tap root) pops out. The seed leaves emerge from within the shell as they push upward in search of light.

One popular way to germinate seeds is placing seeds in a moist paper towel or cheesecloth, in a warm room, (70 – 90 degrees F.) and make sure they are in darkness.

Germinating seeds between moist paper towels virtually ensures success.

At germination, a seed sprouts, sets roots, grows roundish cotoleydon leaves and the first set of true leaves.

Water the cloth daily, keep it moist and let excess water drain away freely. The seed germinates in a few days. The seed contains an adequate food supply for germination and watering with a mild mix of liquid fertilizer will hasten growth. In humid climates, water with a mild bleach or fungicide solution (2 – 5 drops per gallon) to prevent fungus.

Plant seeds once the white sprout is visible. Do not expose the tender rootlet to prolonged, intense light or wind. Plant the germinated seed ¼” to ½ " deep in planting medium with the white sprout tip (the root) pointing down. Lay the seed on its side if confused about which end is up.

The second popular germination method is to sow the seed in a shallow planter (flat), peat pellet or rooting cube and keep the planting medium evenly moist. Transplant 2 – 4 weeks after the seedling emerges from the soil. Use a spoon to remove the root ball and keep it intact when transplanting.

A heat pad or heat tape under or in soil will accelerate germination without drying the soil too fast. A common problem for novices when germinating seeds is over-watering. Keep the soil uniformly moist, but not soggy. Plant seeds in a nursery flat and put them in a warm (not hot) place like on top of the refrigerator. Put a wet piece of paper on top of the soil to retain the moisture. Remove the paper as soon as seeds sprout through soil. Leaving the paper on the soil will inhibit growth. Often seeds only need one initial watering when this method is used. A shallow flat or planter with a heat pad underneath may require daily watering, while a deep, one gallon pot needs water every 2 or 3 days. When the surface is dry (¼-inch deep) it is time to water.

Remember, there are few roots to absorb the water early in life and they are very delicate.

Seedling (cotyledon) leaves are the first to appear after the seed sprouts above the soil. Within a few days, the first true leaves will grow. During the seedling stage, a root system grows rapidly and green growth is slow.

The new root system is very small and requires a modest but constant supply of water. Too much water drowns roots, causing root rot or damping-off. Lack of water dries the infant root system. As the seedlings mature, some will grow faster and stronger.

Others will be weak and leggy. Vansterdan thins out weak plants the third to fifth week and transplants seedlings without any damage.

Soil Temperature

Root cubes, made from rockwool, peat or OasisTM, are convenient and encourage a strong root system. Peat pots are small compressed peat moss containers with an outside expandable wall. The flat pellets pop-up into a seedling pot when watered. Place the seed or cutting in the wet root cube and keep it evenly moist. For clones, make sure to crimp the top in around the stem so firm contact is made between the stem and the growing medium. When roots show through the sides of the cube it is time to transplant. Slit the side and remove the expandable nylon shell of peat pots before transplanting. When completed properly seedlings and clones suffer no transplant shock. Check peat pots or root cubes daily. Keep them evenly moist, but not soggy. Root cubes and peat pots contain no nutrients. Feed seedlings after the first week and clones as soon as they are rooted with ¼ to ½ strength fertilizer.

Inexpensive heat cables double root growth and are easy to use.

The seed intensive method:

Planting many seeds in a small area is also an option. In loose fertile soil, plant seeds from ¼ to ½- inch deep. Some growers set up small 3 x 3 square foot sites, planting three rows with a seed every few inches. Growers with 4 or 5 small patches are virtually guaranteed a harvest. They grow 2 to 5 small plants in various sites. Infrared photography is less effective against small patches. To make more space, growers cull out weak plants at 4 – 5 weeks and remove males as they appear. =========================

Site Selection

Big Steve is too smart to plant on his own land. He rents a country cabin and always plants on public property or other people’s property. Each year he plants in new locations. He likes to plant in low-traffic spaces among small trees and bushes.

Steve also found two different farm fields that have been out of production for a few years. He has had good crops along rivers and streams, but lost crops to floods twice in the last 10 years. When he planted along rivers, he made sure the plants were not visible from the river. Some years….

……Steve planted in buckets in rocky inaccessible terrain. He doesn’t need to prepare the soil, he just brings in grow bags and fills them with soil on the way. The plants don’t grow as big, but are seldom seen because they are growing where nobody goes or would expect them to be. Plants receive good sunlight on rocky hillsides in untillable soil. A site in dense, short bush, like sticker bushes, is another favorite spot. The sticker bushes grow high enough to prevent people from seeing through them and also serve as a deterrent from people and large animals wandering into the site.

“One of my favorite tricks is to plant where there are lots of mosquitoes,” said Steve with a snicker,

“If I can find a place with wasps, too. That’s a double whammy. I think the best site I ever found was next to a skunk’s den, around a skunk spray. I had to smear the inside of my nose with Vicks Vapor Rub to keep from smelling the skunk spray. Nobody went around there!”

“I plant deep inside patches of poison oak, poison ivy or my favorite: stinging nettles. I save seeds and broadcast them. I just cover any exposed skin with a slick rain suit and gloves to protect me. I wash the suit afterward to get rid of the oils. It’s a great way to keep lightweights away from the patch!” said Steve with a smirk, “if there’s a thief that wants my plants, it will cost them!”

Ideal “trails” are “invisible,” have dense undergrowth and lots of sunlight. Growers walk up river and creek beds to avoid detection. Rapid plant growth will erase any damage to the vegetation between trips. Some growers lightly fertilize their trail if they use it more than a few times, but are careful – wild plants are easy to overfertilize. Other growers never take the same path to their gardens and do everything possible to avoid damaging foliage. In late summer and early fall, damaged foliage usually will not regrow. Big Steve always asks himself: Can I see the trail I just made? If not, great, if so hide it! The more difficult it is for you to get to the site, the less likely someone else will try.

Growers who think ahead bring any supplies they need – lengths of PVC pipe, gasoline-powered pumps, water tanks, soil, etc. – early in the spring before underbrush has matured and hide the supplies until needed. Sheltering also protects lightweight plastic from ultraviolet light damage.

Good soil can be in short supply on remote hillsides and is often the richest where grassland vegetation is found. Grasslands recycle nutrients in the soil and form rich fertile topsoil. (See “Soil” in Appendix).

“I order bricks of coconut fiber from out in California. Those bricks are great. They are compact and easy to carry. When I break them up and add water they expand to several times their size,” said Steve, showing me how he loads them into his backpack.

A nearby water source makes a grower’s life easier and safer. Growers trample foliage and risk being spotted when hauling water. The more trips, the more noticeable the trail. Look for a summertime water source that does not dry up. Water consumption is determined by the weather. Dry land crops are possible if it rains once every one to four weeks.

Growers flower summer crops by covering small greenhouses to give plants 12 hours of darkness daily. Crops are ripe in 8-12 weeks. Sunlight is less important yet essential. Five hours of direct midday sunlight per day is necessary for acceptable growth, the more the better. Growers who scout sites during winter months visualize how trees will shade the landscape and the higher path the sun will make in the spring and summer.

Flowering females stand out like a neon sign if surrounding foliage dies back before harvest.

If you can have exclusive access to your marijuana patch by boat, you can cut potential traffic substantially.


The police find hundreds of thousands of cannabis plants annually with aerial surveillance and infrared photography. Large plots are easier to spot than small gardens.

Many communities receive federal funds to eradicate marijuana crops. Some police departments sell the property they confiscate and buy new high tech surveillance equipment, firearms, vehicles and other toys to seek out and destroy marijuana and grower’s lives. Marijuana laws in many states are extremely severe. Law enforcement officials lie, cheat and steal to achieve their means. Do not trust them under any circumstances.

“Report a marijuana grower” programs with a cash reward are common in the USA. Six armed and dangerous narcs came to search my home on the word of a snitch. The narcs would not tell me who squealed on me or why, or if the weasel even existed. If anyone knows or even suspects you are growing marijuana, they have tremendous authority over you. A vindictive enemy can also turn you in with no evidence, even if you are not growing! Growers avoid jealous lovers, family members or malicious “friends”. One of the saddest cases I saw was a daughter that extorted money from her father. The father grew marijuana to ease the pain of his glaucoma. His daughter threatened to have him arrested if he did not sell some of the crop to pay her off. When selecting a site, remember there might be hunters (archers, black powder, rifle and shotgun) as well as mushroom and marijuana hunters or other passers by. Check all the regulations if hunting is popular in your area. The patch will have to be hidden from other wilderness users. There also might be dirt bikers or four wheel vehicles lurking.

Site Preparation

Security is the number one concern in site preparation. Well concealed gardens are harvested, detected plants are not. Prepare growing sites up to 6 months before planting. For best results, let your amended soil sit for at least a month before planting. If the site is on an incline, planting holes must be terraced into the hillside. Make sure the terrace is large enough to catch any runoff water. Make extra gulleys to catch runoff water and channel it to the growing plant. Make a dish around the planting hole to retain water. In heavy brush, clear a few patches so plants get enough sunlight and plant 3-6 plants in each location. When preparing the soil, I cut back all roots from competing plants and till the planting holes 2 – 3 feet square. Soil along a riverbank is almost always fertile sandy loam. Hide the potential garden from river traffic as well as hikers and fishermen. More sunlight is available near the tops of the trees in dense forest. Ingenious growers use deer/elk hunting stands to grow in trees. They set up a pulley system to lift a large container and potting soil up to sit on the plant stand. Install an irrigation hose from the bottom of the tree directly to the plant. The grower passes by weekly with water and manual or battery operated pump to lift water to the plant high in the tree.

A partner is necessary to work on the ground while the other person works in the tree. Smart growers use a safety line and belt and do not spend more than 4 hours off the ground in one day. Accidents happen to tired climbers.