Nutrient Disorders

Marijuana Horticulture

by Jorge Cervantes

When the hydroponic garden is on a regular maintenance schedule, and the grower knows the crop well, nutrient problems are usually averted. If nutrient deficiency or excess affects more than a few plants, check the irrigation fittings to ensure nutrient challenged plants are receiving a full dose of nutrient solution. Next, check the substrate around affected plants to ensure nutrient solution is penetrating entire medium and all roots are wet. Check the root zone to ensure roots have not plugged drainage conduits and are not standing in stagnant solution.

Change the nutrient solution if there is a good flow of nutrient solution through the root zone, but plants still appear sickly. Make sure the pH of the water is within the acceptable 5.5-6.5 range before adding new nutrients.

If changing solution does not solve the problem, changing to a new brand of fertilizer may do the trick. Leach growing medium with diluted 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 earlier stages to avoid serious problems that cost valuable time for plants to recoup. Treatment for a nutrient deficiency or excess must be rapid and certain. But once treated, plants take several days to respond to the remedy. For a fast fix, foliar feed plants.

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 to 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.