Indoor Ant Bait Station

Why another Ant Bait Station?

None of the existing ones work for me.  I deal with Argentine ants, and they’re relentless:

• The liquid bait needs to stay hydrated to stay attractive.
• I need to see activity easily and refill quickly without disturbing them.

Model Features:

• Open design: No cover.  Watch the action.
• Side handle: Easy to move, easy to refill.
• Wide rim: Catches drips and helps prevent mess.
• Shallow trough: Maximizes use of the bait with minimal waste.

Why not just use Painter's Tape?

• I used this for years.  Not terrible but tape is definitely messier and hard to move cleanly.
• Fresh tape has no pheromone trail, so ants ignore it until they rediscover it.
• Tape can leak after long exposure to liquid bait.
• Plastic stations can be repositioned.  Start anywhere, then shift closer to walls or corners.
• Once ants have accepted a station, they leave pheromones on it, so you can move an active station to a stubborn trail and instantly get results.
• These stations are reusable, clean, and easy to move.

Printing tips

• Use a textured build plate, they tend to produce water tight bottom layer.
• Prefer light-color filament so you can see the ants ..
• .. or .. blend the stations with the floor so less of an eye sore.
• Prefer PLA.  PETG sticks too well to PEI plate.

Quick Guide: Baiting Argentine ants

I’m in the Bay Area, California, where Argentine ants have a massive supercolony.  If you have tiny brown ants invading in lines, you probably have them too.  Key facts:

• One queen per ~120 workers, each laying ~60 eggs/day.
• Multiple nests working as a single supercolony, not just one nest to wipe out.
• Most commercial advice ignores the science.

Here’s what actually works:

Step 1: Use Liquid Borax Bait (Not Granules or Peanut Butter Bait)

• Bait: sugar + water.  This is what Argentine ants love to eat.  They slurp it up in a crop and transport back to the nest and share it.  These ants can be thirsty and just go for water, but they won't go for crystalized sugar.  As it dries out, they lose interest.  
• Poison: borax.  The higher the dose, the less they like it.  And too little and it won't be toxic, too much and the ants will die too quickly.

Recipe (optimal range):

• 25% sucrose water → about 2 tsp sugar to 5 tsp hot water.
• Borax at 0.7 – 3% → low enough to keep workers alive, long enough to spread it.

Key to remember: as the liquid bait sits out, water evaporates but the borax and sugar stay behind, so the solution becomes more concentrated over time.  What starts as the right strength can become too strong and repel ants or kill them before they can share it.

⚠ Why not Terro Ant Killer as-is?

• It is not optimal for Argentine ants, and only gets worse as it is left to dry.
• Too thick - dries quickly and loses appeal.
• Too strong - 5.4% borax kills workers too fast.  You really want them transporting your laid out goodies back to the nest.
• Misleading results.  Terro often looks like it worked.  The first wave of workers die and activity stops.  But the colony isn’t gone, only temporarily suppressed.  Scouts will constantly come back and are disinterested in the now-too-dry bait.  They rebuild pheromone trails into your home for another surge and strike again.
• Terro is shelf stable though.  A diluted version won't be.

If you only have Terro, add sugary water to bring down concentration, for example:

2 tsp sugar
5 tsp hot water
1 Terro bait station (0.36 fl oz / 11 cc) (2 tsp)

will yield ~1.5% borax.  This gives you room to add water later and remain toxic.  Or skip Terro entirely and mix your own with store-bought borax.  

Step 2: Keep the Bait Fresh

• Argentine ants may keep coming for weeks, they have endless nests.
• I’ve had a single bait spot active for 3 weeks straight (I'm probably feeding the whole neighborhood).
• Add a few drops of fresh bait or just water daily to keep it moist, they’ll go wild for it again.

References:

• Great watch: Kurzgesagt Video on Argentine Ants
• Very short read: In search of the ‘sweet spot’
• Short and data heavy: Toxicity and Repellency of Borate-Sucrose Water Baits to Argentine Ants
• Very detailed: Low-Toxic Control of Argentine Ants Using Pheromone-Enhanced Liquid Baits