I am not a fan of pesticides - I think they generally do more harm than good. They kill all of the bugs - the good, the bad and the ugly! It takes a lot longer for the beneficials (the good ~ and sometimes ugly ~ bugs) to come back; while the bad bugs literally take over.
So, I am always looking for ways to control bugs the natural or organic way.
Simply pour some corn meal where you have your ant problem. The ants will take it home and have a feast. But they can't digest it properly and will die. (Grits and cream of wheat also work.) Corn meal is inexpensive and if it gets rained on it will still work.
This is not a fast acting solution - they don't drop dead just from touching it, so you will need to have a little patience. But hey, you're a gardener right? Who has more patience than gardeners?
There are other methods to kill ants. For more information go to WikiHow. They have several different ways to try - you can choose for yourself.
Get your hands dirty!
You can make your own cornmeal if you have a wheat grinder - but that's an article for another day.