Baking soda can kill ants, but it’s a slow and unreliable method. Lab tests on fire ants and Argentine ants showed death rates between 42% and 99% over six to seven days when ants were trapped on treated surfaces. In real-world conditions, though, most homeowners see a temporary drop in ant activity followed by the ants returning within two to three weeks. Baking soda typically kills 40% to 60% of worker ants and rarely eliminates a full colony.
How Baking Soda Kills Ants
Baking soda is sodium bicarbonate, an alkaline powder that disrupts an ant’s internal chemistry. When ingested, it reacts with the acidic fluids inside the ant’s digestive system, producing carbon dioxide gas. The ant’s body can’t release this gas, which eventually kills it. The process isn’t instant. Lab studies show baking soda needs five to seven days to kill ants through direct contact, and the lethal dose is surprisingly specific: roughly 7 milligrams per square centimeter of surface to kill half the exposed ants within a week.
The catch is that ants won’t eat baking soda on its own. It has no scent or flavor that attracts them, so you need to mix it with something sweet to trick them into consuming it.
How to Make Baking Soda Ant Bait
The standard recipe is simple: combine one part baking soda with one part powdered sugar. A few teaspoons of each is enough for several bait stations. Mix the two together in a jar lid, bottle cap, or directly on the surface where you’ve seen ants traveling.
Use powdered (confectioners’) sugar, not granulated. This matters for two reasons. First, the fine texture blends seamlessly with baking soda, making it harder for ants to pick out the sugar and leave the baking soda behind. Second, the powdery consistency dissolves more easily, which helps ants consume both ingredients together. If you want a paste that stays put on vertical surfaces or outdoor areas, mix five tablespoons of baking soda and five tablespoons of powdered sugar with about three tablespoons of water.
Place bait stations along ant trails, near entry points like windowsills and door frames, and close to any cracks where you see ants emerging. The more stations you set, the better your chances. Leave them undisturbed for five to ten days before judging results.
Why It Often Doesn’t Work Long-Term
The core problem with baking soda is that it rarely reaches the queen. An ant colony can house thousands to hundreds of thousands of workers, and the queen is the only one producing new ants. Worker ants may carry some baking soda bait back to the nest, but the kill rate of 40% to 60% of workers means a significant portion of the colony survives. The queen continues laying eggs, replacement workers hatch, and ant trails reappear within a couple of weeks.
Mississippi State University Extension explicitly lists baking soda among the home remedies to avoid for fire ant control. Pest control professionals report a consistent pattern: homeowners see early decreases in ant activity, assume the problem is solved, then find the ants back in force. For small, isolated groups of ants in a kitchen, baking soda may knock the numbers down enough to feel like a fix. For an established colony with a nest in your walls, yard, or foundation, it’s unlikely to solve the problem.
How It Compares to Borax and Diatomaceous Earth
Borax is the more proven DIY option. It’s the active ingredient in most commercial ant baits, typically at low concentrations around 5%. Mixed with sugar water or powdered sugar in a similar 1:1 ratio, borax works on the same principle: ants eat the bait and carry it back to the colony. The difference is that borax is more consistently lethal at lower doses, and commercial formulations are specifically designed to be slow-acting enough that worker ants survive long enough to share the poison with the queen. Some homeowners report equal results from borax and baking soda, but borax has more research behind it. One important note: never mix borax and baking soda together, as they react chemically and weaken each other.
Diatomaceous earth works through a completely different mechanism. It’s made of fossilized microscopic shells with razor-sharp edges that damage the waxy coating on an insect’s exoskeleton, causing the ant to dehydrate and die. It kills any insect that crawls through it, and insects can’t develop resistance to it. The limitation is that it only works as a contact barrier. Ants that walk through a line of diatomaceous earth will die, but it doesn’t spread through the colony the way a bait does. Some people use it strategically as a perimeter barrier to funnel ants toward bait stations rather than letting them wander through the house.
Safety Around Kids and Pets
Baking soda is one of the safest substances you can use for ant control. It’s a common cooking ingredient with no toxic effects on children or pets at household quantities. This is its biggest advantage over borax and commercial insecticides. Borax, while low in toxicity, can cause nausea, vomiting, and diarrhea if a toddler eats enough of it. Commercial ant bait stations generally pose little risk due to their low insecticide concentrations, but Poison Control still recommends keeping them out of children’s reach and washing hands after handling them.
If you have curious toddlers or pets that get into everything, baking soda bait is essentially harmless even if eaten. The worst outcome is a mildly upset stomach. That peace of mind may be worth the trade-off in effectiveness for some households, especially if the ant problem is minor.
Getting Better Results
If you want to try baking soda before moving to stronger options, a few adjustments can improve your odds. Place bait directly on active ant trails rather than in random spots. Ants follow pheromone paths, and bait positioned along these highways gets found faster. Refresh the bait every few days, since it loses its appeal as the sugar absorbs moisture or dries out. Set out multiple stations rather than relying on one or two.
Watch for signs that ants are actually eating the bait. If the mixture sits untouched for several days, the ants may be avoiding it. Some homeowners report that ants refuse baking soda bait entirely, possibly because they detect the sodium bicarbonate. In that case, switching to a borax-based bait or a commercial gel bait is your next step. For large colonies, carpenter ants nesting in wood, or fire ant mounds in the yard, professional treatment is more realistic than any DIY powder.