Pasadena Financial Planner -- Pasadena, California | How to Kill Ants with Cheap and Effective Homemade Borax Ant Bait

How to Kill Ants with Cheap and Effective Homemade Borax Ant Bait

Killing Ant Nests with Cheap and Effective Homemade Borax Ant Bait

This article has little to do with personal financial planning, except that one way to increase wealth is to spend less and thus to save more. Because the Pasadena Financial Planner has a web audience that skews toward Pasadena, Los Angeles, and Southern California, I have published this here in the hope that frustrated homeowners will find it and begin winning the battle against these ant hordes.

For fifteen years, I have battled ants on my property in Pasadena, including multiple incursions into my home every year. For many years, I spent much more than I thought reasonable on pest control companies and store bought ant poisons. However, I was never able to get the upper hand. Furthermore, I was not alone. Every neighbor had their own ant war stories, and many had concluded that control is unlikely and eradication impossible.

Two years ago, I set out to research the problem and to find a better and cheaper solution. I had had some success with commercial borax-based ant baits and associated ant bait stations. However, the cost seemed rather high and like an addict, I was forced to keep buying and buying and buying. My wife uses boxes of cheap borax powder in the laundry room, and I wondered whether there was a do-it-yourself approach to ant killing that was effective, low cost, and could be implemented on sufficient scale to eliminate most ants from my property.

With some web research and a bit of trial-and-error, I have come up with an ant killing approach that works and can be implemented on large scale very cheaply. The remainder of this article contains some very detailed bullet points about how to kill ants using just sugar, water, borax, and recycled food containers.

Before, I was spending hundreds of dollars per year in a losing battle with hordes of ants. Now, I am winning while spending less than $20 per year. This article provides everything that people in Pasadena, Los Angeles, Southern California, and in other southwestern states need to fight ants cheaply and effectively using homemade borax ant baiting.


  • Most native ant species do not cooperate — one nest fights another and there is a natural population control. However, much of the American southwest has been taken over by an invasive species of small, black Argentine ants. Argentine ants nests do not fight each other and sometimes they even share ants between nests. This invasive species has displaced many native ant species. In effect, much of the American southwest has become a massive Argentine ant colony with millions of nests.
  • Ants feed on “honeydew” and the scout ants that you see above the surface bring it back to the nest and share it. Ants that find borax ant syrup think that it is honeydew, and they take it back to the nest.
  • There are probably 100 ants in a nest for every ant you see above ground. Surface poison spraying is not a solution, because it does not affect the nests. If worker and scout ants outside the nest do not return, the queen just makes more.
  • Borax ant bait syrup kills ants in the nest, but researchers do not know exactly why it kills. Borax is a naturally occurring mineral. It is not an insecticide designed to kill ants, but it does kill them.
  • Place ant bait stations with borax syrup where ants will find them — the closer to the nest the better
  • Scout ants must bring the borax bait to the nest for the queen and the nest to eat and die. The borax ant bait syrup recipe below is strong enough to kill ants in the nest, but not so strong that the scout ants die before they can return to the nest with it.
  • I did not invent borax ant baiting. Google “borax ant bait” and you will find a ton of information. However, I did refine the process through trial-and-error to develop this very cheap and effective way to kill these little bugger hordes.

How to make inexpensive ant bait syrup

  • Add to a medium-sized sauce pan: 2 to 3 level tablespoons of Borax laundry powder, 2 cups of regular sugar, and one cup of water
  • You can double the ingredients for a larger batch. This syrup is stable and will keep for a long time a closed container.
  • Bring slowly to a boil stirring as needed. This is like candy syrup, so it can burn on the bottom and sides of the pan, if left unattended and not stirred often.
  • It will turn clear when it boils, and you can turn off the heat once the syrup is clear.
  • Remove from heat and let cool to room temperature over a few hours.
  • Pour the cooled ant bait syrup into a squeeze (not spray) bottle with a conical tip. This will allow you to fill the bait stations through their top holes. If you do not have this kind of bottle, substitute an empty kitchen dish washing soap squeeze container that has been cleaned thoroughly.
  • Transferring the syrup can be a bit messy, so do it over the kitchen sink.
  • Fill the used sauce pan with water and soak a bit; wash with soap and water and all the borax and sugar will be gone. Return to food service.

Free recycled plastic bait stations

  • Beforehand, wash and save many 1/2 cup and 1 cup flexible clear plastic food containers with plastic tops. Clear sides allow for inspection without having to remove the top. You can use opaque food containers, but clear ones are better.
  • Use a hand hole punch to punch two holes in opposite sides of each container and one in top. Small holes allow ant entry, while they slow evaporation. Note that the hole in the top is for adding more bait syrup, when refilling. This avoids having to use your hands to open an active bait station with ants that would swarm over your hands and arms.
  • Many types of clear food container will work, such as those for salsa, olives, pasta, pesto, tapioca, etc. Containers that are a bit flexible are better, since more rigid plastic could split when you use the punch to put holes into the side and top.

Bait station placement

  • Squirt in a couple of generous tablespoons of bait syrup into the bottom of the contained and put on the cover.
  • Locate ant trails and place the bait stations directly on the ant trail.
  • Put a scrap of wood on the top to protect from sprinklers and California rain (ha ha)
  • Put a fist-sized rock on top of every bait station so that wind and leaf blowers with not blow the bait stations away
  • Use multiple containers, because they are free and the syrup is cheap
  • While borax is not highly toxic, be safe and make sure that children and pets will leave the bait stations alone.

Monitoring and maintenance

  • Be patient. Think marathon and not sprint.
  • Ants will find the holes in some of the bait stations and take the bait back to the nest.
  • Check every few days and squirt in a more bait syrup, as needed. If the existing bait syrup still flows, re-baiting is not necessary.
  • Success is indicated by the presence of ants in the bait station (dead or alive).
  • When you have a successful ant bait station that ants have used, never clean it off. Ants leave chemical marker trails for other ants to follow, so don’t wash those off a successful bait station.
  • If ants do not use a particular bait station, move it to where they might.
  • If there are no more ants using the trail, because you have successfully eliminated them, move the bait station.
  • As you succeed, you will tend to move the bait stations further from your house and closer to the edge of the property.
  • Once most ants are eliminated, make sure to check for ant trails every few weeks, and add ant bait as needed.

Other useful notes

  • Do not expect complete eradication, which seems hopeless. But you can get the upper hand and keep the ants under control. They are so pervasive in cities and suburbs that they will repopulate from neighboring lots over time once you stop ant baiting. However, this is a far better approach than expensive and repeated surface spraying that will kill other beneficial insects indiscriminately. Furthermore, this method is designed to kill the queens and knock out the nests.
  • These bait stations can be used inside the home. When you have an ant incursion, place bait stations inside and outside the home. Locate where the ants are entering the home and use a commercial ant killing insecticide spray on just the outside foundation near where they enter to prevent more from coming in. Avoid spraying commercial ant poison inside the home. The ants inside may be numerous, but they will eventually feed on the interior ant bait stations and die. You can vacuum up live ants inside the home with a canister vacuum. In my experience, they never find their way back out of the vacuum canister. Again, control pet and kid access to the interior borax bait stations. However, you can decide whether this is a better approach than spraying insect poisons around inside your home.
  • Cut back any shrub or tree vegetation that touches the house high or low. Ants are natural climbers and once they are on the side of your house they look for ways to get in. Also, do not leave hoses uncoiled. Hoses create ready-made ant freeways with one end of that freeway connected to your home.
  • When possible track ants back to determine where the nest might be. Locating bait containers closer to nests is more effective. This is a trial and error process. If the bait station is placed in the middle of an ant trail, the nest could be in either direction. However, note that ants actually “farm” honeydew using with other insects, such as aphids. The usually occurs in trees, which is why you will often see streams of ants going up and down trees, if you look carefully. These ants are not going up the trees for the view. If you look very closely at the ants coming down trees, you can sometimes see them carrying a tiny bead of fluid. That is honeydew bound for the nest, and the reason why borax sugar syrup ant baiting works. So, if an ant trail leads up a tree, then the nest is likely in the opposite direction. Place more baiting traps on the trail in the direction closer to the likely location of the nest(s).
  • If you find ants running up trees and you locate ant bait stations near the nests, the ants might persist on the path to the tree. Some ants could still use your bait station or they might ignore it entirely, preferring the honeydew from up the tree. In that situation, you could use a commercial ant killing insecticide and spray a ring around the bottom of the trunk of the tree. Ant sprays are insecticides and not herbicides and they usually can be sprayed on non-fruit bearing trees. However, read the label of the insect spray to ensure that there is no warning about trees. When you spray a ring around the base of the tree, you will disrupt access to the ants’ honeydew. Then, the ants are much more likely to feed from your borax ant bait stations, since the nest needs food and your bait station contains bait that seems like honeydew to ants
  • Note that ant nests can be almost anywhere, but they are most likely under patios, rocks, paving stones, and tree roots that do not get soaked regularly by irrigation. Also, ants can travel great distances so that nest could be anywhere on your property or in a neighbor’s lot. You could coordinate with your neighbor to kill ants with this process. However, if you do not cooperate with your neighbors, you can locate bait stations near property boundaries, and still control these long distance ant incursions.