Killing carpenter ants without the chemicals


By CCHRC Staff

The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.

Q: How can I get rid of carpenter ants without using toxic chemicals?

Carpenter ants are tenacious creatures and once they start a nest, they can be difficult to eradicate.

Prevention is always the easiest solution.

If you can keep them from establishing a foothold, you will be better able to protect home and property. Remove any wood scraps and tree stumps from around your home.

Sheets of plywood, old tarps, pallets and anything else that provides ground cover, particularly if it is moist, can provide a staging area that will bring ants that much closer to your home.

Once they gain entry to the house at ground level, ants will often start a nest in an area that is damp or prone to decay. Many times the infestation starts at the foundation. Crawlspaces and basements, and any spots that may be prone to moisture damage, will be especially attractive. Rim joists, areas where decks are attached and areas around improperly flashed windows present places that allow the ants to get started.

The ants do not eat wood, but tunnel into it to make their nests. As a result, rigid foam board, which is often used around foundations, also presents an appealing target.

Even though ants prefer moist areas, they are not limited to that environment and will expand their nest building into walls, floors and even work their way into roofs.

A mature carpenter ant colony will have a main nest and satellite nests, which the ants use to broaden their foraging grounds. If the ants can be traced back to the main nest in the woods, then a localized dose of ant poison can be very effective.

Chemical poisons may work well, however they are the least desirable from both a health and an environmental perspective, especially if there is a chance that pets or children could come into contact with them. Many ant poisons are extremely toxic and if you are considering buying a product, research the long term effects and handling precautions online.

Some insect poisons may break down slowly and can be absorbed into the food chain by nearby plants and animals or dispersed by rains and groundwater. So if the main nest cannot be located and safely isolated, sprinkling poisons liberally around the grounds in the hopes it will kill the ants should be avoided. Generally, chemical ant control should be left to a professional who will be able to determine which product is best suited to a particular application.

A lot of the ant baits sold in the stores are designed for Lower 48 species of ants, and the primary attractant is sweets.

Carpenter ants are foragers that eat proteins (such as insects), so sweets will not appeal to them in the same way.

Occasionally, a carpenter- ant-specific bait will make its way on the shelves, and these can be effective. If you buy an ant bait station and leave it exposed, it may attract pets, squirrels, voles and other animals.

Before you begin an ant control strategy, check with a local exterminator. Some exterminators may have access to effective carpenter ant baits and contact poisons which are not available in stores.

When it comes to nontoxic products, diatomaceous earth is available at many feed and garden stores. It acts as a physical killer rather than a chemical killer by working its way into the ants’ breathing tubes and joints. When the ants clean each other, they can also transfer it among themselves. Again, it will do little good putting it on individual ants, you must find a nest.

The presence of ants can create problems in every part of your home, and repairing the damage can be expensive, so the sooner you eliminate ants, the better.

More information on combating carpenter ants is available at the University of Alaska Fairbanks Cooperative Extension Service at

Alaska HomeWise articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, e-mail us at can also call the CCHRC at (907) 457-3454.