If I Have Ants in My Yard, Should I Treat Them First Before Reseeding?

Ant Problems

• Ants frequently build hills, and those piles of soil and the loosened soil around them may look unsightly. The insects rarely pose serious damage to residential lawns, however, according to a Pennsylvania State University, College of Agricultural Sciences website article. When they nest in your lawn, you may be alarmed to see them swarm at certain times of year, such as spring and summer, but ants' presence doesn’t necessarily mean the grass will die. The grass may be harmed only if ants repeatedly rebuild anthills in the same area, according to North Dakota State University, Cass County Extension.

Beneficial Insects

• Ants are most often a nuisance in homes, which they invade to hunt for food, and sometimes they nest in houseplant pots. Outdoors, however, they are not usually a problem. In fact, they often perform beneficial services in the garden, such as eating nuisance pests. Fire ants, for instance, feed on fleas, ticks, scorpions, cockroaches and mosquito larvae, states a Texas A&M University, Galveston County Master Gardeners online article. They also eat dead insects and help with decomposition. Therefore, avoid treating ants with an insecticide unless necessary. Also, ant insecticides can kill other beneficial insects.

Organic Treatment

• A non-chemical solution to ant infestation is to water anthills, allowing water to flow slowly from a garden hose and into the anthills for about 30 minutes roughly twice each week. That method from the Montana State University Extension's website may cause the ants to leave. Another option is to introduce predatory insects that eat aphids; the honeydew secreted by those insects often attracts ants, according to the University of California Integrated Pest Management Online. Thoroughly drenching ant nesting sites with insecticidal soap also may work. Follow the label instructions for the specific insecticidal soap you use. Usually, though, an insecticidal soap needs to be diluted to 1 to 2 percent strength before it is used; for example, 2 1/2 to 5 tablespoons of the insecticidal soap would need to be mixed with 1 gallon of water. When pouring the solution into anthills in direct or full sunlight or when the temperature is above 90 degrees Fahrenheit, don't splash it on surrounding grass, which could be damaged.

Traditional Insecticides

• Although using insecticides usually isn't necessary, granular insecticide can be used if your ant problem gets out of hand. The best time is when you first see ant appear in spring. Spread an insecticide containing 0.2 percent bifentrin, for example, at a rate of 1.15 to 4.6 pounds per 1,000 square feet, starting at the lowest rate and increasing it, depending on the severity of the ant problem. An alternative is to apply an insecticide containing 0.5 percent permethrin at a rate of 2 to 3 pounds per 1,000 square feet. Spread either insecticide evenly by hand or with a spreader, wearing gloves and watering the product into the lawn thoroughly. If you have pets or children and use an insecticide, then keep them off the lawn until it is dry. Pay attention to temperature warnings on any insecticide's label because some insecticides can harm lawns when they are applied during extreme heat.

Lawn Reseeding

• When ants build hills large enough to smother patches of grass, reseeding the lawn probably will be necessary. In the interim, you can deal with each small anthill by raking down its soil and wetting it with water from a garden hose. That task is usually most necessary when ants are most active, as they are during wet springs, according to the Iowa State University Extension and Outreach's website. If a patch of grass becomes bare, reseed it. If ants carry off grass seeds, treat the ants more extensively before reseeding again.