Spreaders / Stickers

Marijuana Horticulture

by Jorge Cervantes

Smart growers use a surfactant, surface-active substance (adjuvant), which enhances the effectiveness of foliar fertilization.

Spreaders (wetting agents) reduce the surface tension of sprays and keep them from beading up and rolling off foliage. Big, bulbous drops n the leaves mean you need to use a spreader. Flat drops that slide off the foliage mean there is too much spreader. There are nonionic, antionic, and cationic spreaders. The nonionic spreaders that do not ionize in water are the most common, and they do not react with most pesticides. Antionic and cationic spreaders are not used often.

Stickers help the spray adhere to the leaf after spraying, so it does not wash off when it rains or when dew forms. Stickers not only increase adhesion, they slow evaporation, and impart a waterproof coating. Some stickers are spreaders, too. Spreader-stickers allow the stomata on the leaves to be penetrated.

Extender (stabilizing agents) protects applied sprays against the UV radiation and heat that degrade the sprays.

Liquid and powder soaps and detergents act as surfactants, too. But, they are not nearly as effective as horticultural surfactants. Biodegradable surfactants disappear the fastest. Silicone surfactants are also mild insecticides that work to impair pest functions.

Foliar spray concentration is cumulative. Nutrients delivered via the foliage can cause a buildup of salts in and around the leaves. This is similar to the way the salts accumulate in the soil.

Over fertilizing can become one of the biggest problems for indoor growers. Too much fertilizer causes a buildup of the nutrients (salts) to toxic levels, and it changes the soil chemistry. When over fertilized, growth is rapid and lush until the toxic levels are reached. At this point, things become complicated.

Chance of over fertilization is greater in a small amount of soil that can hold only a small amount of nutrients. A large pot or planter can safely hold much more soil and nutrients, but it will take longer to flush if overdone. It is very easy to add too much fertilizer to a small container. Large containers have good nutrient holding ability.

To treat severely overfertilized plants, leach the soil with two gallons of diluted nutrient solution per gallon of soil to wash out all excess nutrients. The plant should start new growth and look better in one week. If the problem is severe and the leaves are curled, the soil may need to be leached several times. After the plant appears to have leveled off to normal growth, apply the diluted fertilizer solution.