Sandi, I'm pretty sure ants do not eat plants. They're in the pots for the moisture. Even leaf-cutter ants don't actually eat the leaves.
http://www.examiner.com/articl...
Rather than use a noxious chemical like Sevin, I'd try dousing the infested pots with a solution of boric acid. It's relatively benign. About a tablespoon to a gallon of water.
