Diatomaceous earth is a material composed of the fossilized skeletons of diatoms, tiny single-celled organisms. The skeletons have sharp edges and are porous, so the material scratches the protective coverings of insects and other pests and absorbs oils. It is particularly effective against soft-bodied slugs and snails that require regular moisture to survive. Diatomaceous earth, available as a powdery substance, is an organic, naturally occurring and nontoxic alternative to chemicals used as pesticides in the home landscape.
Put on a dust mask to handle or apply diatomaceous earth. Although this material is nontoxic, it can still irritate the respiratory tract if inhaled.
Pour or scoop diatomaceous earth into a garden duster or dust sprayer. A duster is not necessary, but makes it easier to apply the material uniformly and relatively quickly.
Dust the lawn area where you want to control pests, applying the material uniformly when the grass is dry and no rain is anticipated for at least a day. If you are using a duster, keep the nozzle close to the ground and sweep the duster back and forth, working from one side of the lawn to the other.
Sprinkle the diatomaceous earth in a protective circle around any particularly vulnerable plants, or dust the entire plant with the diatomaceous earth. If you are applying the material to protect your house against pests like ants, sprinkle the diatomaceous earth as a protective barrier around the structure.
Reapply the diatomaceous earth regularly in moist areas and after each rainfall while the problematic pests still pose a threat.