TERRO liquid ant baits work by letting ants feed on a sweet borax solution and carry it back to their colony, killing the entire nest over days to weeks. Using them is straightforward, but placement and patience make the difference between a few dead ants and a fully eliminated colony. While the reader may have been looking for a video, the steps are simple enough to follow in writing, and understanding the “why” behind each step will get you better results than a quick visual walkthrough alone.
How the Bait Actually Works
The active ingredient in TERRO liquid bait is borax (sodium tetraborate), mixed with sugar and water. Worker ants are drawn to the sugar, feed on the liquid, and then return to the nest to share it with the rest of the colony through a process called trophallaxis, essentially mouth-to-mouth feeding. The borax disrupts their digestive system and kills each ant within 24 to 48 hours.
That delayed kill is the entire point. If the bait killed ants on contact, only the foragers would die and the queen would keep producing replacements. The slow-acting formula gives workers time to spread the poison throughout the colony before they die. This is why you should never spray ants with a contact killer while baiting. You want them alive and carrying bait home.
Step-by-Step Placement
Before placing bait, spend a few minutes watching where the ants are traveling. Rather than killing the ants you see, follow them. Foraging ants typically travel between a food or water source and an entry point, often a crack in a wall, a gap around a pipe, or a window frame. Tracing their path tells you both where they’re coming from and where to put the bait for maximum effect.
Place bait stations directly along the ant trails you’ve identified, as close to the entry point as possible. Common hot spots are kitchens (near sinks, countertops, and trash cans), bathrooms, and laundry rooms, since ants are drawn to moisture, food, and warmth. If you see ants traveling along a baseboard, set the bait right against that baseboard in their path. For the pre-filled bait stations like the T300, you simply snap the tab off the top to open the bait well and set it down. No cutting, no mess.
A few placement principles that matter:
- Use multiple stations. Place them at every trail and entry point you find, not just one location. More stations means more foragers feeding and returning to the nest.
- Don’t move the stations. Once ants find a bait station, they lay a chemical trail for other workers to follow. Moving the station breaks that trail.
- Keep competing food sources away. Clean up crumbs, wipe down sticky surfaces, and seal food containers. If the ants have easier, closer food options, they’ll ignore the bait.
What to Expect in the First Few Days
This is where most people panic and assume the bait isn’t working. In the first day or two, you will see more ants, not fewer. This is a good sign. It means foragers have found the bait and are recruiting other workers to come feed. You might see dozens or even hundreds of ants swarming a single bait station. Leave them alone.
Within a few days, the number of ants visiting the bait should drop noticeably as the borax starts killing workers inside the colony. The full timeline depends on colony size. A small colony might collapse in a few days. A large or well-established colony can take several weeks. Once you stop seeing ant activity at the bait stations, leave them in place for another three to four days to catch any stragglers.
When to Replace the Bait
If the liquid inside a bait station dries out or hardens before the ants are gone, replace it with a fresh one. A dried-out station is useless because ants need the liquid form to feed and carry it back. For the T300 stations specifically, TERRO recommends replacing them every three months even if they still look fine, since the bait loses effectiveness over time. As a general rule, any bait that’s been out for more than a year should be swapped out regardless of appearance.
If ants drain a station quickly, that’s actually useful information. It means you have a large, active colony and should add more stations to keep up with demand.
Which Ants It Works On
TERRO liquid bait targets sugar-feeding ants, which covers most of the species you’ll encounter indoors. Argentine ants, pavement ants, little black ants, odorous house ants, crazy ants, ghost ants, and big-headed ants are all attracted to the sweet formula. These are the small ants you typically see trailing along countertops and floors.
Carpenter ants are a partial exception. They don’t primarily eat sugar, but they do feed on sweets occasionally, so they may take the bait. If you’re dealing with carpenter ants and the liquid bait doesn’t seem to attract them after several days, you likely need a different approach. Carpenter ants nest inside wood and cause structural damage, so they’re worth identifying specifically. They’re noticeably larger than most household ants, usually a quarter to half an inch long and black or dark brown.
Keeping Pets and Kids Safe
Borax is low in toxicity compared to many insecticides, but it’s not something you want pets or children getting into. The bait stations are designed to be difficult for larger animals to access, but a determined dog can chew through plastic. If you have pets, place stations in spots your animals can’t reach: behind appliances, inside cabinets, on high shelves, or behind furniture pushed against the wall.
If a dog does lick or eat a bait station, the risk depends largely on the dog’s size. A large dog that licks a small amount of bait is unlikely to show symptoms. A small dog consuming multiple stations is a different situation. Watch for excessive drooling, coughing, vomiting, or lethargy. If any of those appear, contact your vet or the Pet Poison Helpline. In most cases, the plastic housing of the station is actually a bigger choking or obstruction concern than the borax itself.
Common Mistakes That Reduce Effectiveness
The biggest mistake is killing the ants you see. Spraying foragers with Raid or wiping them up defeats the purpose of baiting. Those ants are your delivery system. Every one you kill is one that won’t carry borax back to the colony.
The second most common mistake is giving up too early. If you place bait on Monday and still see ants on Wednesday, the system is working exactly as designed. People often remove the bait or switch to a spray out of frustration, which resets the process entirely. Commit to the bait for at least two full weeks before evaluating whether it’s working.
Finally, don’t place bait stations in areas you’ve recently cleaned with strong chemical cleaners or sprayed with insecticide. The chemical residue can repel ants or kill them before they reach the bait, and the strong scent can mask the sugar that attracts them in the first place. If you’ve sprayed an area, wait for it to fully dissipate before setting out bait stations.