In the garden, spiders are beneficial insects that trap and eat large numbers of insect pests. Certain types of spiders are deadly, however, and their presence in the home can endanger family members and pets. If you notice unwelcome spiders in your house, you can eliminate them with diatomaceous earth, a natural product made from diatom fossils. Diatomaceous earth shrivels the exoskeletons of spiders and other arachnids and insects. Since it harms beneficial insects such as ladybugs and honeybees it should not be used in the garden.
Purchase natural grade diatomaceous earth powder from a hardware store, drug store or home center. Be sure to select natural grade diatomaceous earth, not the kind used for swimming pool filters.
Shake the powder in a thin layer under appliances and in cracks and crevices.
Shake a thin line of the powder at entry points to prevent spiders and other arachnids and insects from entering the home.
Store the powder in a high cabinet out of reach of children and pets.