Diatomaceous earth works well for a number of pests, including ants. Just don’t breathe it or get it in your eyes – it can damage both eyes and lungs (microscopic but very sharp, which is what kills the insects). For ants in a garden or yard, stir up the ant hill to get them swarming on top, then sprinkle the diatomaceous earth liberally all over the area, let the ants play in it all they want, searching for their “attacker.” Check it tomorrow and you’ll probably find they’re all
Also, go to any do-it-yourself pest control store, purchase plain ol’ boric acid. Heat two cups of water to almost boiling, add about 5 tablespoons of honey, perhaps 3 teaspoons of the boric acid, stir until the boric acid is dissolved and the honey is melted. Then thoroughly wet a paper towel with the mix, stuff it in a plastic cup, bury it up to the top edge in the garden or yard, and let the ants feast. Too much boric acid and the ants sense it and stay away, however. Just be sure not to contaminate any food, thoroughly clean any working surfaces, and don’t breathe the dust as you’re working. I’m told Borax (brand name in the laundry section of the grocery store) will also work, but isn’t as strong (it’s a different chemical derived from borax). We just got borax (in the form of orthoboric acid) at the pest control store – better than a pint container for about $8+change, and that should last a long, long time. While we no longer have a roach problem (almost unheard of in the South!), boric acid is great for roaches, as well as a lot of other insects. Plenty of YouTube videos or other web pages on how to use, mix, etc.