The moderate temps of late combined with the wet soil have kicked the fire ants into high gear building mounds again. So it was time to break out the dish soap again. I think I might have posted about this before but it's been a good while and I'm posting it again for any newcomers.
Fire ants are a scourge in the South. Fortunately for those of you in more northerly regions, your cold winter temps keep the fire ants out. They live in huge nests below ground and build mounds above ground where the sun warms the mounds, providing a nice temp for incubating eggs.
If you stir up a mound with a stick, thousands of ants pour out ready to do battle. Woe be to the person who isn't paying attention to where they are standing and accidentally stands on a small hill while weeding. The bite stings a lot and later a small white pustule forms over the bite. Each ant can bite numerous times. Nasty critters.
In the garden they like to start building just inside or just outside the side boards of raised beds. I usually have to do a periodic patrol to watch for small raised areas and treat them before they get any bigger.
And they will get bigger.
How to deal with them? Well, there are commercial baits that you sprinkle around the outside of mounds. Ants will carry the bait down into the nest and it will kill them. Hopefully. But I can't have that stuff around anything edible and I don't want my cats walking through the bait and then maybe licking their paws later. If you mess with the mounds, like quickly scuffing off the top with your boot heel as you walk by, they will move. I used to do that to get them to move out of garden walkways but it doesn't work inside the beds.
One day at the feed and seed, a lady there told me that 1/4 cup of Dawn dish soap in a gallon of water would kill them. Just pour the whole gallon in one mound. I tried it on a mound that appeared right alongside a bush bean row, figuring if it killed a few plants there were plenty more others growing. By golly, it worked! The beans didn't mind a bit and the ants were gone.
I got to thinking and remembered from a hort class that ants have a waxy coating that protects them. It allows them to float in large masses during floods. Soap interferes with that coating so they drown in the mounds when the Great Dawn Flood comes calling. Actually, soap is soap so I now use plain old dish soap from Sam's, the pink stuff in a gallon jug for $5-something. Nowadays almost all dish soaps are phosphate-free. Check the label.
1/4 cup added to 1 gallon of water. Hold the jug about chest high and pour slowly right in the middle of the mound. If you see run off, move the stream around a little until you hit the sweet spot where there's no run off. Then let it just pound down into the mound. It's nicely flooding all those little tunnels under there. The next day the top of the now-flat mound will be covered with thousands of dead ants.
The underground nests are so large and go so deep that you will never get the queen with this method and they'll pop up again maybe 10' away but it will be a while and they'll be out of your bean row or whatever.
Cold weather is supposed to move in this weekend so that will knock back activity for a while as they move back down deeper to stay warm. Yesterday I got all the ant mounds in the garden. In a little while I'm about to go out and deal with larger mounds in the yard, jugs of soap in hand. Death From Above!