I have become Death, destroyer of worlds. For ants.
I mixed honey and Borax (found in the laundry section of the grocery store) to make a paste and spread it where the ants are. I found a big nest in the roots of a tree. The weather is warmer, so they don’t seem to be around the house as much, which is a good thing.
From Wikipedia (http://en.wikipedia.org/wiki/Boric_acid):
Boric acid was first registered in the US as an insecticide in 1948 for control of cockroaches, termites, fire ants, fleas, silverfish, and many other insects. It acts as a stomach poison affecting the insects’ metabolism, and the dry powder is abrasive to the insects’ exoskeleton.
Boric acid is generally considered to be safe to use in household kitchens to control cockroaches and ants. Homemade ant bait can be made by dissolving 1 teaspoon powdered boric acid and 10 teaspoons sugar into 2 cups (~ 500 mL) of water; this mixture can then be absorbed into cotton balls which are left near ant trails. This reportedly will be carried back into the ants’ nest, killing any ants that eat it, potentially destroying the entire colony.
Boric acid is also made into a paste or gel form as a powerful and effective insecticide much safer to humans than many other insecticides. The paste or gel has attractants in it to attract insects. The boric acid slowly causes dehydration.