"Zikes! There are tiny ants marching all over my kitchen counters!"
Ants can be a real nuisance in the home, especially when they take up residence in your kitchen. They can fit through the tiniest crevices, and once they've found a source of food, they will keep coming back for more.
To get rid of ants for good, you need to use a treatment that kills the entire colony, including the queen back in the nest. Don't waste your time squishing the ants on your counters, because as long as the colony is actively nesting nearby, more ants will appear. Don't bother with ant sprays or other pesticides that kill only the wandering workers, either.
Ant baits, whether homemade or commercial, are the treatment of choice for eliminating kitchen infestations. Ant bait combines a desirable ant food with a pesticide. Worker ants carry the food back to the nest, where the pesticide works on the entire colony. You can make an effective ant bait using boric acid, a low toxicity pesticide available in hardware stores and pharmacies.
Which Kind of Ants Are in Your Kitchen?
Ants that you'd find in your kitchen usually fall into one of two groups: sugar ants or grease ants. Before you make and use homemade ant bait, you'll need to confirm which kind you have.
From an entomological perspective, there's really no such thing as sugar ants. People use the term sugar ants to describe any number of ants that happen to like sweets. Depending on where you leave, your sugar ants may actually be Argentine ants, odorous house ants, pavement ants, or some other kind of ants.
Grease ants, also referred to as protein-loving ants, prefer proteins or fats over sugars. This doesn't mean they won't eat sweets, but they're more interested in food with some protein content in it. Grease ants include little black ants, big-headed ants, and pavement ants, among others.
So how do you tell which ants you have? Do a taste test. Put a teaspoon of jelly and a teaspoon of peanut butter, and a teaspoon in the area where you see the most ant traffic. You can tape down a piece of waxed paper, or use a paper plate, and put the baits on that if you'd prefer not to have jelly and peanut butter on your counters or floor.
Which food did the ants prefer? If they went for the jelly, you'll need to make a sugar ant bait. Ants that prefer peanut butter will respond to a protein-based bait. Now you're ready to make your homemade ant bait.
What Is Boric Acid?
Whether you have sugar ants or grease ants, boric acid is an effective, minimally toxic pesticide that can be used in a homemade ant bait. Both boric acid and sodium borate salts are derived from the element boron, which occurs naturally in soil, water, and rocks. Boric acid was first registered as a pesticide in the U.S. in 1948, and was re-registered in 1993.
Boric acid is listed as a low to very low toxicity pesticide, but that does not mean it's nontoxic. Virtually any substance can be harmful or fatal if used improperly (even water!). Read the label carefully, and follow any directions or cautionary information on the boric acid package.
You can purchase boric acid at your local pharmacy or hardware store. It's commonly used as an antiseptic or mixed with water for use as an eyewash. For use in homemade ant bait, you'll need to purchase it in a powder or granule form.
How Does Boric Acid Work?
Boric acid works primarily as a stomach toxin on ants. The worker ants will carry the bait food, loaded with boric acid, back to the nest. There, the ants in the colony will ingest it and die. The boric acid seems to interfere with their metabolism, although scientists aren't exactly sure how it does so. Sodium borate salts affect an insect's exoskeleton, causing the insect to desiccate.
How to Make and Use Homemade Ant Bait
Sugar Ant Bait Recipe
Mix 2 tablespoons of mint jelly with about ¼ teaspoon of boric acid powder. Research suggests that mint jelly is the best sugar ant lure, but you can also try another jelly flavor if you don't have mint jelly in your fridge already.
Grease Ant Bait Recipe
Mix 2 tablespoons of peanut butter, 2 tablespoons of honey, and about ½ teaspoon of boric acid powder. Protein-loving ants respond best to a bait made of both protein and sugar.
Using the Ant Bait
Caution: Keep children and pets away from the ant bait mixture. Although boric acid is considered to have low toxicity, you don't want your dog or cat licking up the bait, nor should you allow children to come in contact with it. It's always better to be safe! Store the boric acid and any extra bait mixture where children and pets cannot access it.
Place your ant bait in an area where you see ants the most. You want the bait to be somewhere along their regular travel path. Use masking tape to secure a square of waxed paper or cardboard, and place the ant bait mixture on it. If you chose a good location and prepared the right kind of bait, you'll probably find ants swarming around the bait within a few hours. If you don't, try moving the bait to a different location.
You will need to replace the bait regularly with a fresh batch, as the ants won't be interested in jelly or peanut butter once it dries up. Continue putting out bait until you no longer see ants.
- Ant Baits: A Least Toxic Control, University of Nebraska-Lincoln, accessed May 1, 2012
- Boric Acid (Technical Fact Sheet), National Pesticide Information Center
- Making Your Own Ant Bait, Michigan State University Extension
- Boric Acid (General Fact Sheet), National Pesticide Information Center (PDF)
- "Sugar" Ants, Washington State University Extension