Ant hills are distinct mounds of fine soil that appear on a lawn’s surface, created as worker ants excavate their subterranean nests. The presence of these mounds creates an uneven, bumpy surface, which can interfere with consistent mowing, leading to scalped patches of turf. Furthermore, the soil piled over the grass can smother the underlying turf, damaging the health and appearance of the lawn. Addressing ant hills restores the lawn’s smooth, uniform aesthetic and protects the grass from localized damage.
Non-Chemical Treatment Methods
One immediate, non-toxic approach is to use boiling water, which physically destroys the ants and collapses the surface tunnels. Pouring a large volume of nearly boiling water directly into the center of the mound can eliminate many workers instantly and disrupt the upper colony structure. However, this method carries a risk of scalding and killing the surrounding grass, so application must be precise to avoid damaging the turf.
A less aggressive liquid treatment involves a solution of dish soap and water, which serves as a suffocant and contact killer. Liquid dish detergent contains surfactants that break down the ants’ protective outer layer, leading to dehydration and death. A mixture of about two ounces of soap per quart of water poured directly into the hill is most effective in the early morning or late evening when more of the colony is present inside the nest.
Another physical control method uses food-grade Diatomaceous Earth (DE), a powdery substance made from the fossilized remains of microscopic aquatic organisms. This powder is abrasive to insects, damaging their exoskeleton and causing them to slowly dehydrate. Sprinkling the DE directly onto the ant hill and surrounding trails is an option, but its effectiveness is diminished if the powder becomes wet.
Chemical and Targeted Bait Options
For a comprehensive and lasting solution that targets the entire colony, chemical treatments are categorized into fast-acting contact killers and slow-acting targeted baits.
Contact products, such as liquid sprays or insecticidal dusts, provide immediate results by killing any ant they directly touch. These fast-acting insecticides are useful for quickly eliminating visible foraging workers and can be applied directly to the mound. However, contact killers rarely penetrate deep enough to reach and eliminate the queen, allowing the colony to potentially rebuild or relocate.
For long-term eradication, slow-acting baits are considered the most effective strategy. These products, often in granular or gel form, are formulated with a delayed-action poison mixed with a food attractant. Worker ants mistake the bait for food and carry the poisoned substance back to the nest, where it is shared with the queen and other colony members.
To maximize the effectiveness of granular baits, they should be sprinkled in a ring a few inches away from the ant hill, not directly on top of it. This placement ensures foraging ants encounter the bait and carry it back without disturbing the nest entrance. The delayed toxicity is intentional, allowing the worker to return to the nest and spread the poison before succumbing to its effects, thereby eliminating the colony at its source.
Application Safety and Lawn Repair
When applying any ant treatment, following all safety instructions on the packaging is necessary. Always wear appropriate protective gear, such as gloves, and ensure children and pets are kept away from the treated area until the product has dried or settled according to the manufacturer’s directions. It is important to remember that broad-spectrum insecticides can unintentionally harm beneficial insects, which requires careful, targeted application to the ant hill area only.
Once ant activity has ceased, the next step is to address the cosmetic damage left by the mound. The loose soil from the ant hill should be carefully brushed or raked away from the lawn surface to prevent smothering the existing grass. The disturbed area can then be leveled by adding a small amount of topsoil or a thin layer of topdressing material. Finally, the bare patch of turf should be repaired by reseeding with grass seed or patching with a small piece of sod.