With all the time and effort you put into your garden, there's just no way to be happy about fire ants marching through it. Since they're never just passing through, their presence poses a big problem for you and your garden. Don't be fooled by their small size---fire ants are aggressive and can leave a lasting sting for those who aren't careful. With a little creativity and caution, you can send these little invaders packing.
Mix dish soap into a bucket of water and pour sudsy water around your garden wherever you see fire ants. You may have to repeat this process periodically to convince the fire ants to move elsewhere.
Slice oranges in half or in quarters and place them around your garden. The ants will climb all over it to gather food. When birds flying overhead see the oranges they will gladly swoop down and pick them up, taking many ants with them.
Cornmeal is said to kill fire ants when they eat it. Try sprinkling cornmeal in your garden wherever you see fire ants.
Use a long-handled shovel to scoop up a large piece of the fire ants' nest---ants and all---and fling it downwind as far as possible. This is most effectively done on an afternoon when you know the temperature will be below freezing during the night. If it's summer, fling the ants into a hole in a shady spot and place a piece of dry ice on it. Fill the hole with fresh soil and pack it down with the shovel. Any ants trapped underground will freeze, and those left above ground will have a difficult time getting back to their nest.
Pour boiling or scalding water into the fire ant mound and stir it all around with a long-handled shovel to make sure the water goes deep into the earth. This may take more than one attempt to be effective.