Mix equal parts boric acid with sugar or flour. Stir the two together in a bowl.
Turn your ShopVac to the leaf-blowing setting. Not all ShopVacs can be used for this project because not all ShopVacs come equipped with the blowing feature. Make sure that you have or rent the correct ShopVac before trying to perform this procedure.
Put on a cleaning mask and protective eyewear.
Pour out a small amount of the boric acid mixture on the floor just inside the entrance of the crawlspace.
Turn on the ShopVac and blow the boric acid mixture into the crawlspace. The blow feature on a ShopVac is extremely strong, so you will only need to turn the machine on briefly so that the mixture is blown into the space.
Things You Will Need
- Boric acid
- Sugar or flour
- Small bowel
- Protective glasses
- Protective mask
- If you notice that the roaches are still roaming around in your crawlspace, you may need to repeat the process with more mixture. Another option is to open the crawlspace and place a lid of the mixture at the entrance. The roaches will be attracted to the starches, and the mixture will stick to their legs, eventually killing them.