Borax works for ants. Even a tiny amount is toxic to insects. Terro ant killer now is made with borax. Myself when I find a outdoor anthill I just pour granular lawn insect killer on and around the hill.Buy a box of grits. Don't water the garden and make sure it's dry. You can sprinkle them on the garden and on the floor in your house. Grits swell in water and since ants have to get water after eating they die because ants don't fart.