Q: My family and I live on an old homestead in the Texas hill country near New Braunfels. We love it here except for a persistent problem we've been having with the local ant population. I've tried controlling the little critters with a commercial insect spray, which temporarily gets rid of the mounds, but often the ants congregate around porches, the yard, and the garden without any evidence of a nearby hill. (We've even had them appear in a frenzy in our closets, with no trails to tell where they were coming from!)
I don't mind sharing this parcel of land with a few of the insects, but the population around these parts is definitely out of hand. Is there any organic control we can use to discourage the ants from entering our premises?
A: Attempts at controlling ants will be more effective if you can find where they're entering and try to stop them there. If you can't determine the entrance, apply controls to all likely places: around doors and windows, along exterior foundations, under the house, and in the cellar.
A wash of pure vinegar applied generously around doors and windows is a good barrier. It could also be used around food storage cupboards and cabinet tops and on interior woodwork where ants are climbing. Another control is silicon powder mixed with pyrethrin. There is a commercial blend called Silox, or you can make your own mix of diatomaceous earth (which is mostly silica) and pyrethrin. The sharp edges of the silica particles cut up the ants' exterior coating, causing them to dehydrate, and the pyrethrin poisons them. You could apply this powder in less visible areas, such as inside cupboards and closets, in corners, in the basement, and anywhere outside around entrances and foundations.
Susan Ervin is a longtime organic gardener and former agricultural researcher at the New Alchemy Institute. She is now working on her own land in western North Carolina.