If you freak at the sight of a spider in your house, you’re not alone. Up to half of women and 10 percent of men fear spiders. Psychologists think that fear of spiders may be a “disease-avoidance” behavior that goes back thousands of years, but whatever. You can make your home a spider-free zone by dusting crevices, corners, and the spaces under beds and furniture with diatomaceous earth (DE), a natural mineral dust that dries out spiders within days after they come into contact with the sharp prehistoric particles.
Because DE kills spiders by physically drying them out, it remains effective indefinitely as long as it stays dry. Reapply after vacuuming — the idea is to have a light layer of the dust in places where spiders or other insects are likely to walk or crawl. Using too much at once may backfire, causing them to avoid the place altogether. In addition to spiders, you can use DE to control roaches, carpenter ants, and even centipedes that come inside your house.
DE is most effective on pests that live in dry habitats so that they are under constant moisture stress — the typical life situation of most house spiders and insects that wander in from outdoors. Particles of DE scratch and abrade the spiders’ bodies, causing them to dry to death. DE that ends up in your vacuum cleaner bag may be good, too, in that it will help to kill any live insects present in the bag.
DE is widely available from companies that sell organic pest control products (you can use our Organic Pest Control and Garden Products Finder to locate a source). In addition, you will need a small handheld puffer to apply the dust to spidery hangouts without breathing it in. These cost from $8 to $15.
Contributing editor Barbara Pleasant gardens in southwest Virginia, where she grows vegetables, herbs, fruits, flowers and a few lucky chickens. Contact Barbara by visiting her website or finding her on Google+.