Don’t Rake or Spray—This Is the Only Way to Kill Ants

If you see dirt mounds appearing in your lawn, it’s most likely ants, and it’s not something you want to put off. Left to their own devices, ant colonies can quickly swell and damage your lawn. While ants don’t generally eat grass, the mounds and large network of underground tunnels often damage roots, creating bare patches in your lawn. 

Spring is the time when ant activity in your yard heightens and mounds appear, according to Nicole Carpenter, president of Charlotte, N.C.-based Black Pest Prevention. “Argentine ants, pavement ants, fire ants, and odorous house ants are the most common ant species infesting yards ,” she says “They might have different food preferences, but the overall behavior and elimination methods are the same.”

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How to get rid of ant mounds in your yard

Many homeowners take a direct approach and remove these mounds with a rake or shovel or by using “kill-on-contact” pesticides. While leveling an ant mound or taking out ants crawling around it may be satisfying, it isn’t effective. 

Ant colonies expand well below the soil surface, extending more than 6 feet deep into your yard. If you take out that mound, the ants will only dig another one. Using contact sprays as opposed to a delayed release poison is also counterintuitive, according to Carpenter. “Killing traveling ants is the worst mistake homeowners can make because this is how the poison never reaches the colony,” she says. 

To truly eliminate nests, Carpenter advises taking a more strategic approach:

Step 1: Use Slow-Acting Ant Baits

When ants enter a slow acting bait station, they become covered in a pesticide that isn’t designed to kill immediately. Instead it takes about 24 to 48 hours to work. This gives the worker ants time to return to the nest and spread the poison to the entire colony, including the queen. 

“Bait stations are effective because you might never even see the nest, meaning you can’t reach or treat it directly,” Carpenter says. “Using the baited stations is how you delegate the job to the ants themselves.” 

Note: Be patient when using ant baits. It can take anywhere from a few days up to two weeks to work, depending on the size of the colony. It’s also normal to see more ants at first in your yard as they will be drawn to the bait. 

Step 2: Choose the Right Bait

To be successful, the bait has to match the ants’ diet, according to Carpenter. “Argentine ants and odorous house ants are attracted to sugary foods, while others like pavement ants and fire ants prefer protein or grease,” she says. Check the label on the ant bait and make sure it’s targeting the ants you’re seeing in your yard. 

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Step 3: Strategically Place the Baits

Place the ant baits close to the mounds. As worker ants come and go, they’ll pick up the poison and distribute it amongst the rest of the colony. 

“If you don't know where the nest is but you regularly see ants in large numbers, place bait stations along their trails or near where you see activity — ideally, during cooler parts of the day when they’re actively foraging,” she says. 

Prevent Future Ant Activity

Once you’ve solved your ant mound issue, take measures to prevent them from coming back:

• Maintain a Perimeter: Carpenter recommends positioning two to three outdoor ant baits around your yard, changing them out every three to four weeks as they wear out. 

• Remove food sources: Keep a tidy yard. “Yards with pet food left outside, fruit trees or fallen fruit, trash, mulched paths or beds, leaky trash cans, and aphids on plants are at higher risk, so keep things clean and control those sources,” Carpenter warns.

Bottom Line 

When you see ant mounds popping up around your yard, rather than reach for the ant contact spray or a shovel, go with a slow-acting bait. Physically removing the ant mound or killing ants you see crawling around only gives you the illusion that you’re eliminating the problem. By using slow-acting bait stations, matching the bait to the ant type, and strategically placing those baits near the mound, you can eliminate an ant colony within a couple of weeks. Once you do, prevent them from returning by removing food sources and periodically trading out old baits for fresh ones.