- Aug 28, 2013
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Actually, I don't think it's ineffective when it gets wet. For a garden you have to put it back down after a rain, because it either washes away or washes into the soil, since it's so fine. DE is diatomaceous earth, which is filled with crushed diatoms. Diatoms are mostly unicelluar plankton with shells made out of silica (basically glass). Food-grade diatomaceous earth is ground fine enough that it should have no impact on the digestive system of animals (and people), but it's deadly when it gets inside the microscopic workings of insects. Getting silica wet won't dissolve it and shouldn't alter its structure in any way.