I live in southern California, where the seasons are flood, fire, and pestilence. We seem to be constantly battling ant invasions. They come in when it's too wet outside, too hot outside, or too dry outside. Basically, there are a couple of ideal weeks each Spring and Fall when we AREN'T fighting them off. As a result, I've developed a few techniques.
Step 1: Getting Ready: Borax, Sugar, and Hot Water
The ants usually come in for water - we're having a severe multi-year drought and the air is as dry as toast out there - but they are happy to stay for food and they're fond of sweets. Now, I don't mind ants out in the ecosystem (my yard, that is) but I'm pretty territorial when it comes to the house. However, I'm on a budget and I don't like exposing my family to toxic chemicals if unnecessary, so I've found a cheap and effective way of fighting them off that doesn't expose us directly to poisons. You'll need to be patient for a few hours while it works, though. All you will need is borax, sugar, and hot water. You can buy the borax at the grocery store in the laundry aisle. One box should last you a couple of years.
Step 2: Preparing the Bait
- Place 3 teaspoons of sugar in a small, heatproof bowl
- Add 1 teaspoon of borax powder
- Add 1/4 cup of hot water
- Stir until completely dissolved. The mixture should be transparent and not too syrupy.
Step 3: Setting the Trap
Now spoon some of the borax/sugar liquid into a plastic bottle cap, not too full, and add a toothpick. The toothpick allows you to direct the ants into investigating the contents of the cap. You can prop one end of the toothpick up against the wall right where the ant line is. In this case, I was working in the bathroom and could only find two ants, since my usual methods keep them under control for the most part. It wasn't long before one of them had found the "treat" on his own.
Now you need patience. Don't actually kill the ants once they've found the bait, at least not those in the line leading to and from the bait. Let them have it. They'll share it with their colony. While you're waiting, follow the line to find out where they're coming into your home, and note the spot.
I've seen the bait, when left sitting out for a day or two, form a skin on top that becomes increasingly tough and eventually hard and glass-like. I think that the syrup clogs the ants' digestive system, in addition to whatever toxicity it has. You'll see the ants in the line moving slower and slower and becoming fewer and fewer as the hours pass. (If the mixture begins to get too thick, add a few drops of water on top and stir with the toothpick to prevent the skin from forming on top.)
Step 4: Pressing Your Advantage
Now that the ants are gone, help them forget where you live. Try to block up the opening where they were entering your home. You can caulk, or just use hot glue or even toothpaste if you're in a hurry. In the kitchen, I have EVERYTHING sealed up in the pantry with plastic bags, something I learned after a particularly horrifying invasion of epic proportions. Borax did the trick there, too. These last steps are particularly important to make your life easier in the long run. If you don't want to bag everything up all at once, just start sealing up the containers as you open them for the first time. Re-use the bags as needed. Soon, everything will be ant-proof. Oh, and don't forget the dog's and cat's food dishes. I bought inexpensive dishes with a "moat" around them, but before I found these I made my own moats by placing the food bowl in a larger dish full of soapy water.