Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

rest of the mineral nutrients are listed in their elemental form that represents the actual content. Most often, the mineral elements used in the fertilizer formulas are listed in chemical compounds on the label. Look at the fertilizer labels to ensure that the elements, especially trace elements, are chelated and readily available for root absorption. Also, be careful about having too much sodium in your water/nutrient solution. The sodium will block potassium and several other nutrients, causing deficiencies and slow growth.
    Nutrients in the United States are measured in parts-per-million (ppm), even though they are expressed as a percentage concentration on the label. The ppm scale is simple and finite-almost. The basics are simple: one part per million is one part of 1,000,000, so divide by one million to find parts per million. To convert percentages into ppm, multiply by 10,000 and move the decimal four (4) spaces to the right. For example: two percent equals 20,000 ppm. For more information on ppm and Electrical Conductivity, see Chapter Twelve, “Hydroponic Gardening.”
    Fertilizers are either water-soluble or partially soluble (gradual-release). Both soluble and gradual-release fertilizers can be organic or chemical.
    These are the suggested soluble-salts fertilizer recommendations for indoor cannabis cultivation. The values are expressed in parts per million.
Chemical Fertilizers
    The diversity of hydroponic fertilizers is amazing. Local shop owners know which ones work best in the local climate and water. Local storeowners know a lot about the local water and the growers’ needs. They are in a perfect position to develop their own nutrient solution or adapt one that works well with their water. A few manufacturers do not do their homework and make bad nutrients. Most manufacturers are conscious and manufacture excellent fertilizers. As always, read the entire fertilizer label and follow the directions.
    Soluble-chemical fertilizers are an excellent choice for indoor container cultivation. Soluble fertilizers dissolve in water and are easy to control, and they can be easily added or washed (leached) out of the growing medium. Control the exacting amounts of nutrients available to the plants in an available form with water-soluble fertilizers. The soluble fertilizer may be applied in a water solution onto the soil. In general, high-quality hydroponic fertilizers that use completely soluble food-grade nutrients are the best value. Avoid low-quality fertilizers that do not list all necessary micronutrients on the label.
    Chemical granular fertilizers work well but can easily be over applied, creating toxic soil. They are almost impossible to leach out fast enough to save the plant.
    Osmocote™ chemical fertilizers are time release and are used by many nurseries because they are easy to apply and only require one application every few months. Using this type of fertilizer may be convenient, but exacting control is lost. They are best suited for ornamental, containerized plants where labor costs and uniform growth are the main concerns.
Organic Fertilizers
    Organically grown cannabis has a sweeter taste, but implementing an organic indoor garden requires horticultural know-how. The limited soil, space, and the necessity for sanitation must be considered when growing organically. Outdoors, organic gardening is easy because all of the forces of nature are there for you to seek out and harness. Indoors, few of the natural phenomena are free and easy. Remember, you are Mother Nature and must create everything! The nature of growing indoors does not lend itself to long-term organic gardens, but some organic techniques have been practiced with amazing success.
     
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    These are the suggested soluble-salts fertilizer recommendations for indoor cannabis cultivation. The values are expressed in parts per million.
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    Most indoor organic gardens use potting soil high in worm castings, peat, sand, manure, leaf mold, compost, and fine dolomite lime. In a container, there is little space to build the soil by mixing all kinds of neat composts and organic nutrients to cook down. Even if it were possible to build the soil in a container, it would take months of valuable growing time and it could foster bad insects, fungi, etc. It is easier and safer to throw old, depleted soil outdoors, and start new plants with fresh organic soil.
    Organic nutrients, manure, worm castings, blood and bone meal, etc., all work very