Carpenter ants are among the the largest ants in the United States, measuring up to 20 mm—or roughly ¾ of an inch long. Most often black but sometimes red or yellow, carpenter ants live both indoors and outdoors, nesting inside moist, decaying wood (like in old tree trunks, or rotting wooden boards). While they burrow and colonize inside wooden materials like termites, unlike termites, they do not eat wood. Instead, their diet is like that of other ants, consisting mostly of sweet foods and meats.
Because they do not eat wood, carpenter ants aren't nearly as damaging to homes as termites. However, if given enough time, a highly developed and mature colony can cause extensive damage to nearly any wooden structure. With queens living up to 25 years, it’s not hard to imagine how costly a carpenter ant infestation can be to a homeowner. If you’re seeing these little carpenters crawling throughout your home, or looking to prevent an infestation before it takes hold, here’s 10 Tips to Get Rid of Carpenter Ants.
Prevention is always the best form of pest control. Follow these simple guidelines to keep carpenter ants out of your home.
- Keep your home clean—particularly the kitchen, flooring, windowsills and countertops. Without a food source, ants will have no reason to enter your home.
- Seal all food in tightly closed containers. Keep all food storage areas free of crumbs and residues (Tip: wipe off all those jam, sauce and honey containers).
- Never leave food remains or dirty dishes in the sink.
- Take the trash out regularly, and keep all trash cans clean and sealed.
- Any spilled food should be cleaned up immediately.
- Seal any cracks, crevices and holes—all potential ant entrances—with caulk or other sealant.
- Remove or remedy all sources of unnecessary moisture both inside and outside your home, including: leaky plumbing, basements, crawl spaces, A/C units, hoses, faucets, sprinklers, clogged drainage areas, etc
- Remove possible nesting spaces from your yard, such as: woodpiles, wooden yard equipment, brush, dead or dying trees & tree strumps, unused dog houses, furniture, and any other possibly moist, wooden items.
- Keep tree limbs and branches away from the walls of your home. Carpenter ants use these as bridges to enter your home.
- Do not store lumber or firewood inside or right outside your home.
Find The Nest
The most effective methods for ridding yourself of carpenter ants all involve locating and treating their nests directly. Carpenter ants nest in moist, decaying wood. These nests can be located either inside or outside the home, and unless you actually follow the trailing ants back to their origin, it’s not always easy to determine which. However, in general, if you find carpenter ants inside your home during late winter or early spring, chances are the colony is located indoors. Here’s some tips for locating a carpenter ant colony:
- Look for frass. Frass is finely ground wood debris that resembles sawdust. It’s the result of carpenter ants boring into wood to build their nests. If you see this in your home, the carpenter ants are somewhere inside.
- Damaged wood on or within walls, doors, cabinets, and wood beams is a good indicator of an indoor colony. Look specifically for sandpaper-smooth carpenter ant galleries and holes.
- Place attractants like dog food, jam or other sweets where you most commonly spot carpenter ants. Using their trail, attempt to find the location of their nest.
- If you have woodpiles or other wooden debris inside or just outside your home, check them thoroughly—the ant colony could be inside.
If you were able to find the carpenter ant nest (and it was located outdoors), this natural method is a way to attack the ant colony directly. It’s simple: boil a few liters or more of water and then pour it directly into the nest (this can be dangerous, so please exercise extreme caution). Adding a naturally sourced and water-soluble insecticide, essential oils, or soap to the boiled water will make this approach even more effective. You may have to repeat this process two to three times to completely eliminate the colony.
Sugar and Baking Soda Bait
A simple and natural carpenter ant bait can be made by mixing equal parts baking soda and powdered sugar. Strategically place this mixture in shallow dishes in the locations with the most ant traffic. These can also be placed outside, particularly near doors and windows. The sugar in the mixture attracts the ants, while the baking soda naturally kills them (for chemical reasons, baking soda is deadly to ants).
Like most ants, carpenter ants use pheromone trails for navigation and communication—it’s also how they find food. Essential oils can be used to disrupt these trails, which ultimately disorients and deters ants. Lemongrass, peppermint, clove, cedarwood, tea tree, orange and lemon oil are all effective.
Dampen a cotton ball or kitchen towel with an essential oil of your choosing. Use this to wipe windowsills, baseboards, the perimeters of countertops, door frames, and any potential entry points. Repeat daily until ant population disappears. Your chosen oil can also be diluted with a carrier oil to create a natural ant-killing spray.
Soap & Water
A simple mixture of soap and water is toxic to carpenter ants. Mix one part natural dish soap to two parts water in a spray bottle. Spray as needed to kill ants and eliminate their pheromone trails. Continue to treat problem areas until the ants no longer return.
Made from crushed algae fossils, Diatomaceous Earth is a well known natural pesticide. This abrasive material damages the exoskeleton of ants that come into contact with it, eventually killing them. Spread DE throughout ant problem areas and directly on the colony’s nest if possible. Diatomaceous Earth is especially effective for combatting carpenter ants, which regularly die from consuming it.
Non-toxic Insecticides—Both Indoor and Outdoor
Plant-based, over-the-counter insecticides are often the easiest and most effective option for completely eliminating a carpenter ant colony. The best approach is to treat both outside and inside your home. Non-toxic indoor insecticides can be used as both a repellent and a contact killer. Plant-based outdoor insecticides also work as both deterrents and spot killers. For best results, apply non-toxic outdoor pesticides along fence lines and your home’s foundation; this will create a repellent barrier to keep ants from entering your home. Treating your entire yard will help to eliminate any active outdoor carpenter ant colonies.
Vinegar is an extremely effective natural carpenter ant deterrent. It disrupts their pheromone trails and the smell prevents them from returning. Mix a 1-to-1 ratio of water to vinegar in a spray bottle (both apple cider and white vinegar will do). Shake the solution and then spray along baseboards, door frames, window sills, countertops, and directly on the nest if possible. Repeat the process daily or as needed to repel carpenter ants. Vinegar is a natural disinfectant and multi-surface cleaner—so feel free to use the spray liberally.
Cinnamon & Cinnamon Oil
Not unlike the previously mentioned essential oils and vinegar, cinnamon and cinnamon oil deter ants by interfering with their pheromone trails. Dispense the cinnamon in whatever form throughout ant problem areas and directly on the nest if possible. When used around windowsills, baseboards, near doors and alongside countertops, cinnamon helps prevent carpenter ants from entering your home.