An even better idea is to find the ant's nest and use a bait on them.
Do this -- Squish one of the ants between your fingers. Then smell
your crushed-finger-ant. If it has a seriously-strong odor smelling
something like DEET then what you have are Odorous House Ants, and they
cannot be controlled just using bait.
If you want to go 100% organic, then use a little dish soap with water
to treat your plants. It works well, but you'll have to use it often.
If the ants dont have a powerful odor or no odor at all, bait will
probably work. Try to find one listed for Fire Ants, Pavement Ants,
Pharoah Ants and Little Black Ants which will help ensure your ants
will take the bait. Expect results in 2-4 weeks.
One more thing:
Follow the directions on the packaging EXACTLY.