How to Get Rid of an Ant Colony? | Kill the Queen, End the Problem

Killing the queen ant is the only way to truly eliminate an entire ant colony, and the most effective DIY approach is a borax bait that the workers carry back into the nest.

Ant mounds in the yard aren’t just ugly—they mean a thriving colony below ground. Spraying the ants you see on the surface does almost nothing, because the queen stays deep in the tunnels, producing more workers. To get rid of the colony for good, you have to target the queen directly. The two proven routes are a borax-based bait (poison delivered by the ants themselves) or scalding hot water poured straight into the mound. The approach you choose depends on your tolerance for plant damage and whether the infestation covers a wide area or a single mound.

Why You Must Kill the Queen—Not Just the Workers

Worker ants live only a few weeks, but a queen ant can live for years, laying thousands of eggs. Killing workers without reaching the queen is a temporary fix—the colony simply produces more. In multi-queen species like fire ants, you have to eliminate all the queens at once. Surface sprays, mound flattening, and repellents only address the symptom, not the problem.

Borax Bait: The Best DIY Way to Poison the Queen

A borax bait works because ants eat the sugary mixture and carry a dose back to the nest to feed the queen and the brood. The poison builds up over a few days and kills the colony from the inside out, including the queen. The University of Florida’s IFAS Extension recommends this as a primary method, and it’s relatively safe for yards when kept away from children and pets.

To make it yourself, mix ½ teaspoon borax, 8 teaspoons powdered sugar, and 1 cup warm water into a paste. Place small containers of the mixture near the mound entrance or along active ant trails. Ants will carry the mixture inside, and within a week or two, colony activity should stop.

For a more permanent solution, check out our tested roundup of the best ant colony killers if you prefer a commercial bait that’s pre-mixed and ready to apply.

Boiling Water: Direct but Destructive

The problem is that hot water kills any plant roots it touches, leaving a brown patch on the lawn. It also doesn’t always reach the queen if she’s deep enough. This method works best on a single mound in a non-vegetated area or a spot where some grass damage is acceptable. Pour slowly and avoid splashing yourself.

Success State: The mound stays quiet for 3–4 days and no new ants appear at the surface—meaning the colony was destroyed.

What About Dish Soap, Diatomaceous Earth, and Natural Repellents?

These options have real limits. A dish soap solution can kill ants on contact by breaking down their protective coating, and a 1-to-1 vinegar-and-water spray disrupts scent trails, but neither reaches the queen. Diatomaceous earth (DE) works by absorbing the oils on an ant’s exoskeleton, but it only kills the ants that crawl through it—not the colony below. Peppermint oil, cinnamon, coffee grounds, and ground cayenne pepper repel ants from treated areas, but the colony just finds another route or moves a few feet away. Natural repellents are useful for keeping ants out of the house, but they won’t eliminate the colony in your yard.

The Right Use Case for Each

• Borax bait: Best for killing the whole colony—use it first.
• Boiling water: Good for a single mound if you accept plant damage.
• Diatomaceous earth: Works as a barrier for trails, but expect to reapply.
• Vinegar or peppermint oil: Confuses foraging ants and cleans trails—fine for indoor lines, but no colony kill.

FAQs

Does flattening an ant hill get rid of the colony?

Flattening the mound only disrupts the nest entrance—the queen and the brood remain safe underground. Ants usually rebuild within a day or two.

How long does a borax bait take to kill an ant colony?

Depending on colony size, it typically takes 7–14 days. You’ll see a gradual drop in ant activity as the poison reaches the queen and the brood stops being fed.

Can I use gasoline to kill fire ants?

No. Pouring gasoline or diesel into mounds is toxic to soil, pets, and people, and it’s illegal in many areas. Stick to bait or boiling water.