Boric acid has long been used commercially and residentially to effectively kill cockroaches, as well as other insect pests. Making your own boric acid solution for spraying roaches is easy and inexpensive. Whip up only as much as you think you'll need at any given time, because it doesn't store well. Wear gloves when preparing this brew, which may irritate the skin of sensitive individuals.
Bring 1 qt. of water to a rolling boil and pour it into a plastic pail immediately.
Add 1 cup of powdered boric acid, and stir vigorously to dissolve thoroughly.
Funnel the boric acid solution into an empty plastic spray bottle.
Spray the boric acid solution generously in places where you've observed the presence of even a single cockroach. Pay attention to moist areas, which roaches prefer.
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Axl J. Amistaadt began as a part-time amateur freelance writer in 1985, turned professional in 2005, and became a full-time writer in 2007. Amistaadt’s major focus is publishing material for GardenGuides. Areas of expertise include home gardening, horticulture, alternative and home remedies, pets, wildlife, handcrafts, cooking, and juvenile science experiments.