Copper (Cu)

Marijuana Horticulture

by Jorge Cervantes

Copper is concentrated in the roots. It is also used as a fungicide.

Copper is a component of numerous enzymes and proteins necessary in minute amounts, copper helps with carbohydrate metabolism, nitrogen fixation, and the process of oxygen reduction. it also helps with the making of proteins and sugars.

Copper deficiencies are not rare. Young leaves and growing shoots wilt, leaf tips and margins develop necrosis and turn a dark, copper-gray. Occasionally, an entire copper-deficient plant wilts, drooping even when adequately watered. Growth is slow and the yield decreases. A small deficiency can cause new shoots to die back.

Apply a copper based fungicide such as copper sulfate. Do not apply if the temperature is above 75F to avoid burning the foliage. Apply a complete hydroponic nutrient that contains copper. Cannabis plants seldom develop a copper deficiency.

Copper, although essential, is extremely toxic to the plant even in minor excess. Toxic levels slow to overall plant growth. As the toxic level climbs, symptoms include interveinal iron chlorosis (deficiency) and stunted growth. Fewer branches grow, and the roots become dark, thick, and slow growing. Toxic conditions accelerate quickly in acidic soils. Hydroponic gardeners must carefully monitor their solution to avoid copper excess.

treat toxicity by flushing the soil or the growing medium to help expel the excess copper. Do not use copper-based fungicides.