Ants don't eat plants - if you have ants all over them, there's probably aphids infesting them, the ants collect their honeydew - treat for the aphids and the ants disappear.

I think it you look closely you will see that the ants aren't eating your plants they are milking the aphids that are there and sucking the sap. Spray with a garlic solution or if you use eco washing up liquid you can add a few drops to a spray bottle and squirt them with that,

just find out wear the antsseam to be going in the ground and get some ant powder . the all female workers take this to the queen and the grubs and kill the lot . as the other people say the ants get sweet juice from theaphids rear end and in reply they defend the aphids which unless in pots are your plants real problem .