BIG ant infestations here on the farm every year. This year early on I tried CINNAMON! Sprinkled in all the windows, under the sinks, along floor boards in less than conspicuous places, behind the toilet, at the door jams.....so far it's working amazingly well, smells nice, and isn't a chemical. Bought the cheapest jar of ground cinnamon I could find; the ants don't have snooty tastes.
Jan in VA