Getting rid of kitchen ants requires two things: killing the colony that’s sending workers into your home, and sealing the gaps they’re using to get inside. Spraying visible ants only kills the foragers, which the colony replaces within days. Bait is the most effective approach because workers carry it back to the nest, where it spreads to the queen and the rest of the colony. Most infestations clear up within one to two weeks with the right strategy.
Identify Which Ants You Have
The type of ant in your kitchen determines what bait to use and how urgently you need to act. Most kitchen ants are small, about 1/8 inch long, and fall into a few common species.
Odorous house ants are the most frequent kitchen invader. They’re black, about 1/8 inch, and give off a rotten coconut smell when crushed. They nest under sinks, appliances, and along foundations, and they’re drawn to anything sweet. Pavement ants are similar in size but reddish-brown to black, and they eat both sugary and greasy foods. You’ll often spot their small dirt mounds in cracks near your home’s foundation.
Carpenter ants are larger and more concerning. They’re black (or black with a red head and thorax) and chew tunnels into damp or damaged wood to nest. They don’t eat the wood, but they can cause structural damage over time. If you’re seeing large ants, especially near areas with moisture problems, you may need professional help rather than a DIY approach.
Clean Up What’s Attracting Them
Ants follow pheromone trails left by scouts that found food. Every crumb, sticky spot, or pet food dish is a signal that brings more workers. Before doing anything else, deep-clean your kitchen: wipe down counters and stovetops, sweep under appliances, and clean inside cabinets where spills might have gone unnoticed. Store sugar, honey, cereal, and other open foods in sealed containers.
Take out trash daily and rinse recycling before it sits. Pet food bowls are a major draw, so pick them up between feedings or place them in a shallow dish of water to create a moat ants can’t cross. Once you’ve removed their food sources, ants are far more likely to take the bait you set out because it becomes the best option available.
Use Bait, Not Spray
This is the most important point: resist the urge to spray ants with contact killer. Spraying kills the visible ants but leaves the colony intact, and the colony can contain tens of thousands of workers plus one or more queens. Worse, sprays can repel ants away from bait stations, making the problem harder to solve.
Bait works because ants carry it back to the nest, where they share it through feeding. The active ingredient is dilute enough that workers don’t die immediately, giving them time to distribute the poison throughout the colony. Place bait stations directly along the ant trails you see and near their entry points. Don’t disturb the trails or clean them up while baiting is active, because those trails are guiding ants straight to your bait.
Commercial gel baits and bait stations are widely available and effective for most kitchen ants. For ants attracted to sweets (like odorous house ants), use sugar-based baits. For pavement ants or others you notice around grease or protein, try a protein-based or grease-based bait. If one type isn’t getting picked up after a day or two, switch to the other.
Making Your Own Bait
A homemade liquid bait works well for sugar-loving ants. Research from the University of California, Riverside found the effective range is 0.5% to 1% boric acid mixed into a 25% sugar water solution. That translates to roughly 1 teaspoon of boric acid powder per 2 cups of water with 1/2 cup of sugar. A large-scale field trial using a 0.5% boric acid concentration reduced ant numbers by about 80%.
The key is keeping the boric acid concentration low. Too much kills the workers before they make it back to the colony. Soak cotton balls in the solution and place them on small pieces of foil or in shallow lids along ant trails. Replace them every few days as they dry out. Homemade baits need to stay out longer than commercial ones because the active ingredient is more dilute.
How Long It Takes
Expect to keep seeing ants for a week or more after you start baiting. This is a good sign. It means workers are actively feeding on the bait and carrying it home. According to NC State Extension, you should leave bait in place for three to four days after you see no more signs of ant activity. Pulling it too early leaves surviving colony members to rebuild.
For larger colonies or species like Argentine ants that form supercolonies with multiple queens, the process can stretch to two or three weeks. If you’re still seeing heavy ant traffic after two weeks of consistent baiting, try a different bait formulation or consider calling a pest control professional.
Diatomaceous Earth for Problem Spots
Food-grade diatomaceous earth (DE) is a powder made from fossilized algae. Under a microscope, the particles have sharp edges that cut through an insect’s outer shell, causing it to dehydrate and die. To humans and pets it feels like a fine, soft powder and is safe for use in homes.
DE works best as a barrier rather than a colony killer. Apply a thin, barely visible layer along baseboards, window sills, and cracks where you’ve seen ants. If you find a large group, spread powder directly over them and create a perimeter around the area. Outside, sprinkle a band at least 6 to 12 inches wide around your home’s foundation, paying extra attention to known entry points.
After 24 to 48 hours, check whether ants have rerouted around the treated areas. Once the ants are gone, clean up the DE and wash those surfaces thoroughly. This removes the pheromone trails that would attract future scouts. One limitation: DE loses effectiveness when wet, so it won’t work in damp areas or outdoors after rain.
Seal Entry Points
Ants can enter through gaps as small as 1/16 of an inch. Once you’ve eliminated the current colony, sealing entry points prevents the next one from finding its way in. Focus on these areas:
- Door thresholds: Apply caulk along the bottom outside edge and sides of thresholds, where tiny gaps commonly form.
- Windows: Caulk cracks around window frames, especially older ones that have shifted over time.
- Utility openings: Seal gaps where pipes and wires enter your home, including around outdoor faucets, gas meters, dryer vents, and cable lines. These are among the most common ant entry points.
- Foundation cracks: Fill with caulk, cement, or expandable foam depending on the size of the gap.
For most kitchen-area sealing, an acrylic latex caulk works well. It’s paintable, cleans up with water, and stays flexible enough to handle minor settling. Clear-drying caulk is more forgiving than pigmented types if you’re not experienced with a caulk gun.
Safety Around Kids and Pets
Commercial ant bait stations contain insecticide at very low concentrations. The National Capital Poison Center notes that unintentional exposures to ant baits generally pose little risk of toxicity. A toddler who tastes the contents might develop nausea or vomiting, and skin or eye contact can cause mild irritation, but serious poisoning is uncommon.
Still, place bait stations where children and pets can’t reach them: behind appliances, inside cabinets, or under furniture along walls. Don’t pry open sealed bait stations. If you’re using homemade boric acid bait, keep it on elevated surfaces or in areas blocked off from pets, since the sugar solution is attractive to dogs and cats. Wash your hands after handling any bait product.