How to Make and Use Homemade Ant Killer

DIY ant bait traps that really work

Ants on an orange.
Getty Images/Moment/Susan Thompson Photography

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.

Ant baits, whether homemade or commercial, are the treatment of choice for eliminating kitchen infestations. Ant-killing 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 killer using boric acid, a low toxicity pesticide available in hardware stores and pharmacies.

Identify the Ants

Before you make and use homemade ant bait, you'll need to confirm which kind you have. Ants that you'd find in your kitchen usually fall into one of two groups: sugar ants or grease ants. 

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 live, 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.

To determine which kind of ants you have, do a taste test. Put a teaspoon of jelly and a teaspoon of peanut butter in the area where you see the most ant traffic. Tape down a piece of waxed paper, or use a paper plate, and apply the bait on the paper or plate to avoid smearing jelly or peanut butter onto your counters or floor.

Next, determine which type of baits the ants prefer. If they went for jelly, 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.

Ingredients: Break Out the Borax

Whether you have sugar or grease ants, boric acid is an effective, minimally toxic pesticide that you can use to create effective ant-killing bate. Both boric acid and sodium borate salts are derived from the element boron, which occurs naturally in soil, water, and rocks.

Boric acid is a low-toxicity pesticide, but that does not mean it's nontoxic. Virtually any substance can be harmful or fatal if used improperly. 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. To create a homemade ant killer, you'll need to purchase borax in a powder or granule form.

How to Make Homemade Ant Killer

Use either of the following methods, depending on what kind of ants you have:

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.

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.

Use and Application

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-killing 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.

How It Works

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 the ants' metabolism, although scientists aren't exactly sure how it does so. Sodium borate salts affect an insect's exoskeleton, causing the insect to desiccate.

Tips and Warnings

Keep children and pets away from the ant bait mixture. Although boric acid has 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. Store the boric acid and any extra bait mixture where children and pets cannot access it.

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.

Sources:

  • 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