Mixing baking soda and sugar does kill ants, but it works slower and less completely than most people expect. Lab tests show death rates of 42 to 99 percent in fire ants and Argentine ants over six to seven days, but those results come from controlled settings where ants were trapped on treated surfaces. In real homes, baking soda bait typically kills 40 to 60 percent of worker ants, and full colony elimination is rare.
How Baking Soda Kills Ants
An ant’s stomach maintains a highly acidic environment, with a pH around 2 to 3. Baking soda (sodium bicarbonate) is a weak base with a pH of about 8.3. When it hits that acidic stomach, a straightforward chemical reaction kicks off: the bicarbonate reacts with the acid and releases carbon dioxide gas.
The key detail is that ants can’t burp or vomit. The carbon dioxide has no way out, so it builds up inside the ant’s digestive tract and eventually kills it. This process isn’t instant. It takes roughly five to seven days for baking soda to kill ants, even under ideal lab conditions.
The Basic Recipe
The standard mix is equal parts baking soda and powdered sugar. One tablespoon of each is enough to start. Stir the two together thoroughly so the ant can’t separate the sugar from the baking soda.
Use powdered sugar, not granulated. The fine particles blend evenly with the baking soda, making it impossible for ants to pick out only the sweet stuff. Granulated sugar crystals are visibly larger than baking soda grains, and ants can tell the difference. Powdered sugar also dissolves faster, which helps when ants are foraging for quick energy sources.
You can use the mix dry or add a small amount of water to create a paste. A paste works better in spots where wind or foot traffic would scatter a dry powder.
Where to Place the Bait
Put the mixture directly along ant trails, near cracks and corners where they enter your home, and close to whatever food source they’ve been targeting. Common spots include near trash bins, along kitchen countertops, behind appliances, and at the base of exterior doors. Use shallow dishes, jar lids, or small pieces of cardboard to hold the bait.
For outdoor use, place the bait near visible ant mounds or along the foundation of your house where trails are active. Keep in mind that rain or heavy moisture will dissolve the mixture quickly, so tuck outdoor bait under overhangs or in sheltered areas when possible. Refresh the bait every few days if it gets wet or crusty.
Realistic Timeline and Results
Don’t expect overnight results. Give the bait five to ten days before judging whether it’s working. You’ll likely notice fewer ants along their usual trails within the first week, which means foragers are dying before making it back to the colony.
Here’s the honest limitation: baking soda bait kills individual worker ants effectively, but it rarely wipes out an entire colony. Most homeowners see an initial decrease in ant activity followed by ants returning within two to three weeks. That’s because the queen and deeper colony members may never encounter enough bait to be affected. Worker ants do carry food back to share with the colony, but the amount of baking soda that reaches the queen through this process is often insufficient.
For a small ant problem, like a trail of ants that found a crumb under the toaster, this method can be enough. For a persistent infestation with multiple trails or visible nests, it’s better treated as one tool among several rather than a complete solution.
Safety Around Pets and Children
Baking soda is non-toxic to dogs and cats in the small amounts used for ant bait. This is one of the method’s genuine advantages over chemical ant killers. A pet licking a small dish of the mixture isn’t a cause for concern.
That said, if you’re also using borax-based baits alongside baking soda (a common next step when baking soda alone isn’t enough), those do need to be placed out of reach. Tuck borax traps inside cabinets, behind heavy appliances, or in other spots children and pets can’t access. Baking soda bait doesn’t require the same precautions.
Why It Often Falls Short
The 40 to 60 percent kill rate in lab conditions drops further in a real home for several reasons. Ants have other food sources available, so they may not consume enough bait. Moisture can degrade the mixture. And the bait competes with whatever attracted the ants in the first place, whether that’s pet food, fruit on the counter, or grease near the stove.
Colony size also matters. A single ant colony can contain tens of thousands to hundreds of thousands of individuals, depending on the species. Killing even a majority of the foragers you see doesn’t touch the queen, the larvae, or the reserve workers deeper in the nest. The colony simply produces more foragers, and the problem returns.
If you’ve tried baking soda bait for two to three weeks without lasting improvement, the next practical step is a borax-based bait. Borax works through a similar concept (ants eat it, it disrupts their digestion) but is more reliably lethal at lower doses and has a stronger track record for reaching the queen through the colony’s food-sharing behavior. Commercial gel baits use this same active ingredient in a formulation specifically designed to be carried deep into the nest.
Tips to Improve Effectiveness
- Remove competing food sources. Clean up crumbs, wipe down counters, and seal pet food containers. The less alternative food available, the more likely ants are to eat your bait.
- Don’t kill the trail. It’s tempting to spray or squash the line of ants, but you want them alive and carrying bait back to the colony. Let them work for you.
- Use multiple bait stations. Place three to five small dishes rather than one large one, spread along the ants’ active routes.
- Refresh every two to three days. Old bait dries out, clumps, or loses its appeal. Fresh mixture keeps ants coming back.
- Be patient. The five to ten day window is a minimum. Some colonies take longer to show meaningful decline, especially larger ones.