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

deficiencies and excesses in Chapter Eleven to determine the exact problem, and add 10 to 20 percent more of the deficient nutrient in a chelated form until the disorder has disappeared. Leach growing medium with dilute nutrient solution to solve simple overdose nutrient problems.
    Hydroponic gardens have no soil to buffer the uptake of nutrients. This causes nutrient disorders to manifest as discolored foliage, slow growth, spotting, etc., at a rapid rate. Novice gardeners must learn how to recognize nutrient problems in their early stages to avoid serious problems that cost valuable time for plants to recoup. Treatment for a nutrient deficiency or excessmust be rapid and certain. But once treated, plants take several days to respond to the remedy. For a fast fix, foliar feed plants. See “Foliar Feeding” in Chapter Eleven.
    Nutrient deficiency or excess diagnosis becomes difficult when two or more elements are deficient or in excess at the same time. Symptoms might not point directly at the cause. Solve mind-bending unknown nutrient deficiency syndromes by changing the nutrient solution. Plants do not always need an accurate diagnosis when the nutrient solution is changed.
    Over-fertilization, once diagnosed, is easy to remedy. Drain the nutrient solution. Flush the system at least twice with fresh dilute (5-10 percent) nutrient solution to remove any lingering sediment and salt buildup in the reservoir. Replace with properly mixed solution.
    Nutrient disorders most often affect a strain at the same time when it is receiving the same nutrient solution. Different varieties often react differently to the same nutrient solution. Do not confuse other problems–wind burn, lack of light, temperature stress, fungi and pest damage–with nutrient deficiencies. Such problems usually appear on individual plants that are most affected. For example, foliage next to a heat vent might show signs of heat scorch, while the rest of the garden looks healthy. Or a plant on the edge of the garden would be small and leggy because it receives less light.

     
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    Here are some guidelines:
Water when plants are half-empty of water; weigh pots to tell.
Water soil gardens when soil is dry one-half inch (1.5 cm) below the surface.
Water soil gardens with a mild nutrient solution and let 10-20 percent drain off at each watering.
Do not let soil dry out to the point that plants wilt.
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A handle and stand on this pump make it easy to move and mount into a fixed position.

Top feed buckets.

Ebb and flow tables can be the length of a greenhouse. Long tables take a long time to flood and require a huge reservoir of nutrient solution.

Big beautiful buds grow super dense on tables.

Chapter THIRTEEN
AIR

A carbon filter and ozone exchange box dominate the landscape in this Dutch grow room.

Introduction
    Fresh air is essential in all gardens. Indoors, it could be the difference between success and failure. Outdoor air is abundant and packed with carbon dioxide (CO 2 ) necessary for plant life. For example, the level of CO 2 in the air over a field of rapidly growing cannabis could be only a third of normal on a very still day. Wind blows in fresh CO 2 -rich air. Rain washes air and plants of dust and pollutants. The outdoor environment is often harsh and unpredictable, but there is always fresh air. Indoor gardens must be meticulously controlled to replicate the outdoor atmosphere.

Monitor temperature and humidity regularly. The 86°F (33°C) 34 percent relative humidity conditions make plants use more water and less fertilizer. Adjust irrigation schedule to meet needs.

Smoke is immediately sucked out of the room when using this inline fan. The fan demonstration took place at the 2000 CannaBusiness trade show in Germany.
    Carbon dioxide and oxygen provide basic building blocks for plant life. Oxygen is used for respiration–burning carbohydrates and other foods to provide energy. Carbon dioxide must be present during photosynthesis. Without CO 2 a plant will die. Carbon dioxide combines light energy with water to produce sugars. These sugars fuel the growth and metabolism of the plant. With reduced levels of CO 2 , growth slows to a crawl. Except during darkness, a plant releases more oxygen than is used and uses much more carbon dioxide than it releases.
    Roots use air, too. Oxygen must be present along with water and nutrients for the roots to be able to absorb nutrients. Compacted, water-saturated soil leaves roots little or