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Potassium Silicate

Potassium silicate is the potassium salt of silicic acid, and, in formulation, is readily absorbed by the plant. Silicon comprises 32% of the Earth’s crust, and silicic acid salts (silicates) are the most common form of silicon.  Potassium silicate will be used as a broad spectrum, preventative fungicide, insecticide and miticide with optimum control obtained when used under a scheduled preventative spray program. (US EPA)

Potassium Silicate is a natural fungicide; it helps build the plants defense from attacks by insects and fungus. It helps the plant growth by depositing in the epidermal cell walls, enhancing the plant's ability to keep the leaves pointed towards the light source. Potassium Silicate is impregnated in the epidermal cell layer acting as a barrier against penetration of fungal attacks from powdery mildew, black spots, Pythium, phytophthora and many more fungal problems. Potassium Silicate plays an active role in combating fungal growth by the production of polyphenolic compounds; this is a main part of the plants natural defense against fungal and insect attacks.

Potassium Silicate also increases the stem strength, making it easier to hold up more weight, which is always good fro cannabis. Silicate increases the mechanical strength of the plant to help it in extreme heat and cold swings, salt build up in soils or increased TDS in water. It also controls the rate of transpiration of plants. As the plant increases the silicon levels, it increases nutrient uptake and distribution.

Target Pests: Spider Mites, Aphids, Thrips, Whiteflies

Target Pathogens: Powdery mildew, Black spots, Pythium, Phytophthora

Mode of action: The mode of action of potassium silicate is not fully understood. There appears to be both a mechanical mode of action (when applied as a foliar spray), and a physiological mode of action (when translocated within plant tissues) with current research mostly supporting the latter hypothesis. Silicon impregnates along epidermal cell walls (Parry and Smithson 1964). These layers become effective barriers against water loss and fungal infection (Sangster 1970, Takeoka et al 1984). Silicon is also deposited in xylem vessel cell walls, preventing constriction of xylem under high transpiration stress (Raven 1983), and in endodermal root cells, where it acts as a barrier against infection of the stele by parasites and pathogens (Bennett 1982).  University of California Sustainable Agriculture Research and Education Program

Application Tips: Do not allow workers into treated areas for four hours following application. Do not spray when and where bees are foraging.

Potassium silicate is exempt from the requirement of a tolerance in or on all food commodities so long as the potassium silicate is not applied at rates exceeding 1% by weight in aqueous solution and when used in accordance with good agricultural practices.

    Impact on Beneficial Insects: Low

    References

    US Environmental Protection Agency - Office of Pesticide Programs BIOPESTICIDES REGISTRATION ACTION DOCUMENT - Potassium Silicate PC Code 072606

    Marschner, H., Mineral Nutrition of Higher Plants, Academic Press, 1995, pp. 417-426,440-442.