Easy DIY method for getting rid of a carpenter ant infection inside the home without the use of chemicals or other toxic substances.
We’ve had two major infestations of carpenter ants to deal with during the 25+ years of living in our home.
The first occurred shortly after we moved in. Our house was built in 1951 and sits in a semi-rural neighborhood with lots of trees, vegetation, and moisture due to a backyard lake. Needless to say, it is the perfect environment for critters of all kinds including carpenter ants.
The first infestation had me calling the pest control company in a hurry!
Calling Pest Control for Carpenter Ants?
Carpenter ants are huge and very scary looking as you can see from the picture above. While they do sometimes bite, there isn’t any poison, so if you are careful, you can pick them up with your fingers and throw them in the toilet or flush down the drain with no problem.
At the time, though, I didn’t know any of this, so seeing dozens of large ants running around my then retro style 1970’s orange and yellow kitchen was not a pretty sight.
I picked up the phone and called pest control and after a couple of toxic sprayings around our house, yard, and then in our attic over the course of a week or two, the carpenter ants were gone.
The Natural Approach is Very Effective
Our second infestation of carpenter ants happened just a few weeks ago, and this time, I handled it very differently.
Having the knowledge and wisdom of 20 years of green living behind me, I was determined and very confident I could resolve this infestation with zero pesticides and no call to pest control.
My youngest was especially freaked out by the enormous size of the carpenter ants even after I explained that they don’t have a sting like other types of ants and picked up one in my fingers to show her. Unfortunately, my little pep talk and demonstration didn’t do much to alleviate her fears of these intimidating, wriggling creatures.
The carpenter ants were swarming in our kitchen and bathrooms and after starting with just one or two here and there, over the course of a week, they came in by the dozens overnight while we slept making for a very scary turning on of the lights in the morning if you know what I mean. We spent the first 15 minutes of the morning vacuuming them up before we could even get started with breakfast!
Find Where The Ants are Trailing
After watching and observing their patterns over the course of a day or two, I determined that their primary mode of entrance into our home appeared to be the drain of the dishwasher.
Knowing where the carpenter ants are getting into the house is a helpful piece of information, but not entirely necessary if you wish to eradicate them yourself via nontoxic measures.
In our case, the dishwasher drain seemed a likely ground zero, so I mixed up my carpenter ant killer ambrosia and set the bait.
How to Mix Nontoxic Bait
My one cup of ant bait consisted of the following all of which cost less than $1. Believe it or not, this is all that was needed to get rid of ants quickly and easily.
- 1/3 cup of powdered white sugar
- 2/3 cup boric acid (where to find)
That’s it!
Note: you may use borax powder for a less strong mixture.
When I took our container of boric acid out of the garage utility cabinet, it consisted of a bunch of hardened chunks that needed to be pounded out as I hadn’t used it in a long time.  So, I took out my mortar and pestle and pounded out a few big chunks to re-powderize and then measured it into a small ziplock bag that contained the appropriate amount of powdered sugar.
Boric acid is a colorless white powder that is a mild antiseptic, but certainly not a problem to the health of your family even if you touch it with ungloved hands. It is found in nature in some volcanic environments near Tuscany and Nevada.  Boric acid and its salts are found in seawater and plants including almost all fruits.
Keep Away from Pets and Children
Of course, you need to keep it away from small children and pets. It is poisonous if ingested or inhaled in large quantities.
However, it is probably the least toxic form of insect bait you can use around your home. The one exception is diatomaceous earth, which unfortunately doesn’t work as well or as quickly for large ants where I live.
Where to Place the Bait
I placed a couple of tablespoons of the carpenter ant bait in the lid of an empty jar I was going to recycle and placed inside the dishwasher on the bottom near the drain just before going to bed.  Before I did this, however, I was careful to run a load of dishes and empty everything out so the dishwasher was completely void of any plates, glasses, or utensils.
A Happy Ending to our Carpenter Ant Infestation
The next morning we were delighted to see that there were no carpenter ants running around the kitchen! Â When I opened the dishwasher to have a peek, they were swarming around the bait but were totally confined to that area.
I gently closed the door of the dishwasher and left the ants there, happily eating away at the bait they would take back to their nest to kill the whole colony.
It took a few days, but gradually, the carpenter ants swarming inside the dishwasher completely disappeared with nary a stray one left!
When I needed to run the dishwasher in the interim, I simply removed the container of bait, ran a load, emptied the clean dishes, and then replaced the bait near the dishwasher drain.
Simple, effective, non-toxic, and best of all, cheap with no call to pest control to come and spray who-knows-what hormone-disrupting, carcinogenic chemicals around your home for your family to breath and absorb!
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I’m for using nature’s chemistry though we might want to check this out while handling boric acid. Handle with care and keep out of reach of children and pets.
Warning:
Boric acid is probably more toxic to humans than many other registered pesticides. Take a look at the Merk Index for boric acid and you’ll find human toxicity symptoms include: nausea, vomiting, diarrhea, abdominal cramps, circulatory collapse, tachycardia, cyanosis, delirium, convulsions, and coma. Death has occurred from <5 grams (the weight of a nickel) in infants and from 5 to 20 g in adults. The lesson is to treat all chemicals with respect and don't believe just because a compound is organic or natural it is safer than a registered and thoroughly tested substance. In fact it may be just the opposite.
Boric acid is a very mild pesticide. Much safer than the toxic ant killers at the home improvement store! Yes, you must keep away from children and pets as with anything that might be accidentally ingested.
I wouldn’t be taking Merck’s advice on much of anything to be honest! They are on the same level as Monsanto. Trying to scare people away from things that are natural because they don’t make any money on it.
What if you can not find their trail and do. Not know where they are coming from? I am seeing random ones in different rooms after rain. I put some Terri on my kitchen counter and there is no sign that works? How do I find their trail?
Finding where they are coming in is a very important first step. Try to see what room you find the most ants as that is likely to be where they are coming in. Work from there to examine walls, baseboards etc.
Thank you so much Sarah! Hardly seeing any ants at all no, when we do they are very big (bigger than already big ones we where seeing) & we can tell they are in the process of dying. So far I believe we are winning!
Keep the trap fresh and available until you don’t see a single ant for several days. Glad it is working for you so well!
How long did you have to keep the boric acid/sugar mixture out? We have had it out for almost a week and we are still seeing ants, much much less ants but still about 15-20 a day.
It might take awhile depending on the size of the colony. If you are seeing fewer ants, that is a very good sign. Perhaps refresh the bait and keep on it until they are gone. Ants don’t like old bait. The fresher the better.
I put ant trap drops, they ate for 3 days and stopped.. called pest control, they put honey and protein bait, they seem not attracted except few. Many still travel across home. I put Terro liquid , they ate one night and then again started roaming in home. I noticed that the ants roaming around are interested in sugar water as I tried a sample. I am not sure if just boric acid and sugar powder will work or not? If I use water, how much water, sugar and boric acid to use?
At first I thought I had raccoons in my attic and in my kitchen when they was running on my counter, but it was because i wasn’t wearing my glasses. once I put them on it turns out they are just big carpenter ants i guess but i never hear any “hammerin” sounds and it appears they are pretty quiet and they come out at night to gather their food and to pollinate.
The powder mix didn’t work for me, the ants ignored it. I tried mixing it with some jam and that didn’t work either. Finally I dissolved it in water, and that seemed to work, so far. I only ever saw one ant at a time on it, not swarming it as I thought they would, but the number of ants around here has dropped precipitously. We’ll see. I’ve read elsewhere that carpenter ants alternate between sugary foods and protein/greasy foods so if the sugar mix doesn’t work you may want to try some other food.
Do I mix the sugar and boric acid with water or just put the powder mixture out?
Don’t mix in water. Just mix the sugar and boric acid thoroughly.
What do you do about the potential damage to internal wall structures?
I had my first run-in with carpenter ants when I was 9 months pregnant and home from work for the day. They were ALL OVER my kitchen cabinets, just staring at me creepily. I used natural pesticide solutions for awhile and then tried a local pest company but the best solution has been sugar traps.