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17 Essential Elements
Grow Guide: 17 Essential Elements Category: Plant Nutrition
Author: Rodge 420 Post Date: 05-13-2006
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The 17 Essential Elements of Marijuana Nutrition

The Science of plant nutrition might seem complex and difficult, but a grower must understand it to be successful at the outlaw art of marijuana cultivation. Like most other higher plants, Cannabis requires 17 absolutely essential elements for healthy growth. Using only these 17 ingredients, green plants can synthesize millions of chemical compounds, including everything we eat, drink, smoke and wear.

Light - The Number one Plant Nutrient is light. Most people don't think of light as a food, but it really is the most important part of any plant's diet, and Marijuana likes long hours of full, direct sunshine. With modern lighting technology, nature sunshine can be virtually duplicated. There was a time when smoking indoor grass was like sticking your tongue in a light socket, but nowadays even an expert may have a tough time figuring out whether a bud was grown under natural or artificial light. No matter where you grow, make sure your plants get plenty of light.

Carbon - Carbon makes up 45% of the dry weight of tissue in most higher plants. Plants absorb carbon dioxide (CO2) from the air. With good air circulation you will never have a shortage of carbon. But you can also feed extra carbon dioxide to your plants if you wish; carbon dioxide generators are commercially available and are very practical, often necessary, for indoor growers

Oxygen and Hydrogen - Together, these two elements make up another 45% of the dry weight of plant tissue. These vital elements are supplied by water (H2O). Plants that are short on water tend to wilt. One way of providing water to plants that seems to work is the addition of polymers to planting soil. First developed for arid land agriculture, these chemical "slurpers" soak up water when it's available and release it slowly to the plants. Both indoor and outdoor plants seem to benefit from the addition of small amounts of polymers to soil.

Nitrogen - The most common soil deficiency, especially in areas of high rainfall, involves nitrogen. Marijuana plants use nitrogen to make proteins, enzymes, chlorophyll, amino acids, nucleic acids, nucleotides and, best of all, the cannabinoids.
Nitrogen is also the single most difficult element to handle. The most common error for beginning growers is using too much nitrogen. Marijuana is a heavy feeder and will soak up all the nitrogen it can get; the leaves turn a rich dark green, the stalks shoot up and the plants look great. Unfortunately, an excess of nitrogen retards root growth, delays maturity, and inhibits flowering. And if you really pour it on, you can "burn" the plant long before maturity is reached. If you have a short season and want your plants to mature early, it's better to risk a slight, easily remedied nitrogen shortage than pour too much.
If you're trying to grow outdoors anywhere outside the tropics, you must be very careful about how you add nitrogen. Over the years, I've found that a few pounds of well-turned compost provide all the nitrogen my plants need. If a plant seems to be losing its dark-green color, especially in the older leaves. I'll give it a few gallons of dilute fish emulsion fertilizer and a light foliar spray of liquid seaweed (Maxicrop is a good brand).
If you buy commercially prepared potting soil you probably won't need to add any nitrogen to the plants, but I prefer to make my own because I don't trust commercial soil mixes. I know of at least one large reputable soil packager that made a huge batch of potting soil, using sludge from millponds, that had too much boron; nothing planted in it could grow. With plants that are worth over $4000 a pound, I can't afford to trust strangers to make my soil. To be sure it's done right, you have to do it yourself.

Phosphorus - Second to nitrogen as a limiting factor in most soils, phosphorus is essential for the production of a compound called ATP (adenosine triphosphate) that plays a critical role in turning light energy into the energy of chemical bonds. Phosphorus is also part of several proteins, enzymes and nucleic acids that are vital to all plants. Phosphorus deficiency symptoms show first in the more mature leaves, which turn dark green. At maturity, deficient plants are stunted and often show tints of red or purple colors that are caused by buildup of pigments known as anthocyanins. This condition slows flowering in the plant.
Abundant supplies of phosphorus speed maturity and make large flowers. If excess phosphorus is applied, root growth is stimulated, so if you have a short season, risk overdosing with phosphorus rather than underfeeding.
Sources of phosphorus include rock phosphate, colloidal phosphate, bone meal and super-phosphate fertilizer. I prefer nutrients in their organic form because you have a wider margin of error; you are much less likely to damage your plants with organics than with chemicals. In the case of phosphorus, organic forms are relatively slow to go into solution, the soluble forms that can be absorbed by the roots of plants. Colloidal phosphate becomes available to root more quickly than rock phosphate; steamed bone meal dissolves faster than raw bone meal. If you think you need instantly available phosphorus, then you'll have to get super-phosphate; one commonly available form is Blood Food, a 0-10-10 mixture. (By law, the three "NPK" numbers on a fertilizer label indicate concentrations of Nitrogen, Phosphorus and Potassium)

Potassium - Potassium comprises about one percent of the dry weight of most plants, and this element is required for the functioning of a plant's respiratory system, enzyme system and protein synthesis. It also helps the plant maintain "turgor" the internal water pressure that supports it. Wilting is symptomatic of a loss of turgor. The signs of potassium deficiency are dead spots on older leaves, weak stalks, easily infected roots and a tendency to fall over. (Acidic soils are more likely to be deficient in potassium than neutral soils)
The best organic source of potassium is wood ashes, which should be stored in a dry place and mixed into the soil at least a month before planting. Keep in mind that ashes are leached by rain and much of their value will be lost if they are put in the soil too soon; if put there too late, they can burn the seedlings.
When making wood ashes, burn only wood. Do not burn cardboard, magazines, colored paper, lead-painted wood, trash, plastic or anything else. Cardboard contains boron and you could easily create toxic levels by burning too many boxes. The inks used in color printing contain several toxic heavy metals that can be detrimental to plants and their consumers. Coal ashes are not the same as wood ashes and should never be used in garden or pot-plot soil.
A few pounds of ashes per plant is sufficient. Too many Ashes can cause salts to build up in soil.

Calcium - Acidic soils in high-rainfall regions are the most likely to lack calcium. Symptoms of calcium deficiency are twisted and deformed young leaves. The best way to eliminate the problem is to put lime on the soil well ahead of planting. There are several forms of lime available at most garden shops, but avoid hydrated lime and slaked lime because they are too strong. I use dolomite limestone, a relatively mild form.
Much of the calcium in plants acts as a buffer against the accumulation of chemically similar, but toxic elements.

Sulfur - Sulfur is a component in two of the essential amino acids from which all proteins are made. It also plays a role in the synthesis of several vital hormones, although it does not appear in the end product. A common pollutant, it's present in most but not all soils. If you live anywhere near a paper mill or coal furnace, you are more likely to have too much than not enough sulfur. Excess sulfur causes the destruction of chlorophyll, that magic stuff that turns light into plants.
There are some areas where plants can benefit by addition of sulfur. Gypsum (hydrated sulfate of calcium) is often found in garden supply stores, but it's also used in plaster of Paris, so go easy if you decide to add it to your potting mix. If you're in an acid rain area, try using extra lime in the soil. The calcium will help protect your plants from excess sulfur.

The elements listed so far make up the major nutrients or macronutrients, 99.5 percent of the tissue of plants. The rest of the essential elements are called trace elements or micronutrients, several of which are metals, which conduct electrons in cellular processes. Very small concentrations of these metals are required; some of them easily become toxic at higher levels.
These metals are present in most soils, but plants can still show a deficiency of any of them. The problem lies in the chemical nature of the metals, which usually exist in the form of insoluble salts. Insoluble nutrients are useless to plants. Only dissolvable nutrients can be absorbed through the root membranes.
The more acidic the soil is, the less soluble its mineral salts. Nearly all the agricultural soil in the western United States is acidic, with a ph acid-to-base ratio below 7. Adding lime raises the ph and makes the metal salts more available. Chemicals called "chelating agents" are also used to make metals available. Pronounced "keelate" the word derives from the Latin word meaning "claw". A chelate, formed when a chelating agent donates electrons to the metal ions, is both soluble and fairly stable. There are several trace-elements fertilizers that contain chelates and/or chelating agents.

Molybdenum - Most plants need less molybdenum than any of the other elements mentioned here. Only one ten-millionth of the plant is molybdenum, but deficiencies are still common. Severely twisted young leaves and yellowing older leaves are the main symptoms of this type of deficiency. Adding lime can increase the availability of molybdenum.

Iron - The role of iron in plants has been studied for years and is still not fully understood. Without iron, chlorophyll formation stops; the main symptom is yellowing of younger leaves. Chelating agents are used to make iron available to plants, but adding it is usually unnecessary.

Manganese - Manganese deficiencies are not common. Symptoms are yellowing leaves with necrotic (dead) spots. Manganese is an important part of the photosynthetic system, but 50 parts per million (PPM) of a plants dry weight is required for healthy growth.

Magnesium - Magnesium deficiencies are quite common, especially in hydroponic systems. The first sign of a shortage is the yellowing of older leaves; leaf tips will curl upward and start to die. Only 2000 PPM is needed, so if you want to be absolutely sure you won't have a shortage of magnesium, just add dolomite limestone to your mix. In hydro systems, try adding two teaspoons of Epsom salts to every gallon of solution; this should be done every time you change your solution.

Boron - The biochemical role of boron is uncertain, but a plant cannot complete its life cycle without it. Its deficiency is not common; the earliest symptom is a cessation of root-tip elongation, thought to be due to decreased DNA synthesis.
You are far more likely to have a toxic excess of boron than a deficiency. Only 20 PPM is needed by the plant, and at only slightly higher levels, boron becomes toxic. In the unlikely event that you have a boron shortage, a few ashes from cardboard boxes might be enough to solve the problem. Some gardening authorities recommend Boraxo as a source of boron, but very little is needed; about one-teaspoon to100 square feet of soil.

Copper - Only about six PPM of copper are needed by the average plant. Copper is rarely deficient in most soils. In hydroponic systems, excess copper readily becomes toxic.

Zinc - The main symptoms of zinc deficiency are a reduction in leaf size and distortion of the edges of leaves. Chelating agents and commercial trace-elements fertilizers will correct this condition.

Chlorine - Chlorine is rarely deficient in nature and never deficient in civilization, where water is chlorinated. Symptoms of a deficiency are leaves wilting and turning a bronze color, with dead spots. If you don't have chlorinated water and do see these symptoms, try a very dilute solution of chlorine bleach and water. Your plants only need 100 PPM of chlorine, so you should only use a tiny bit of bleach.

Prevention - The best way to avoid nutrient deficiencies is to use a rich and diverse blend of organic material in your planting soil. If you blend moderate amounts of many materials, like aged compost, wood ashes, bone meal, lime, seaweed, rock phosphate, colloidal phosphate, greensand, cottonseed meal, blood meal, crushed oyster shells, straw, leaf mold, worm castings, guano, granite dust, etc.. You will end up with enough of everything your plants need, including all the trace elements.
Above all, go easy on the nitrogen and heavy on the potassium and phosphorus, so you will get short, strong, early-blooming, full-flowering, potent plants.

This article was copied by Rodge 420 from HIGHTIMES magazine 9/95 volume #253 and is published in the book " The Best of Sinsemilla Tips".

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