Composting is something I adore. It’s a fantastic approach to decreasing and recycling your waste while also creating nutrient-dense soil for your garden at the same time.
But, I’ll admit that when it came to allowing insects, worms, and other creatures into the compost, I had to tamp down my natural instincts to eliminate them. For me, infestations of insects always mean “problem”.
But as I learned how beneficial they are to the composting process, I eventually grew fond of the beetles, worms, and all of the other beneficial creatures that had made an ecosystem out of my compost.
But as it turns out, there is one backyard pest that you should not allow into your compost pile: ants. Keeping ants out of the compost bin is one of the most difficult problems I’ve ever had to deal with.
Ants are rarely useful in composting; instead, they tend to cause more harm than good. And once these industrious little things get established in your compost pile, it can be a nightmare trying to get rid of them for good.
If you are struggling with this issue, you have come to the right place.
Let my struggles inform your own ant-elimination strategies: In this post, I’ll show you nine tried-and-true methods for keeping ants out of your compost bin, methods that I personally have had success with.
Are Ants Really a Bad Thing for Your Compost Pile?
Having ants in your compost bin may not appear to be a problem at first.
After all, there are many insects and other organisms that are good for the compost pile, accelerating biodegradation of organic waste, and excreting substances that help our compost nourish plants and soil.
It appears that ants would be a great addition to this backyard environment. They consume organic waste, dig tunnels, and perform all the other functions that helpful insects do.
So, why are we trying to eliminate them from our compost bin and keep them out?
In a nutshell, ants are seldom beneficial to the compost pile and disrupt processes we want to encourage.
Ants do tunnel through the compost, which is true, but many kinds of ants are just a menace in every sense of the word, with quite a few common varieties acting highly predatory toward other insect species that we want living in and developing our compost.
Given enough time, a colony of ants may wipe out virtually any life they can reach, and allowing them to kill off the other insects and organisms in the compost pile will serve only to delay the needed decomposition of the compost pile.
They might be a “natural” part of the environment, but allowing ants into your compost will set up a new order, one where they rule and your compost stalls.
9 Easy Ways of Controlling Ants in Your Compost
Taking the appropriate steps early enough will keep ants from getting into your compost pile in the first place, and prevent the ones already there from organizing.
But should you detect a significant movement of ants in your pile, or see signs of an established colony, you might need to step up efforts to full-blown eradication.
Below is a list of nine proven methods for blocking, repelling, and killing ants in your compost pile, listed generally from the most destructive to the least destructive.
1. Chemical Pesticide
When everything else has failed, your compost is swarming with ants and the situation seems hopeless, it may be time to call in the heavy artillery.
Modern pesticide chemicals will kill ants essentially upon contact, and utterly eradicate them- eggs, larvae and all- and will allow you to get your compost back in no time.
Pesticides are not selective in the insects they kill. It will exterminate ants, along with all other insects and arthropods in the compost bin or pile.
This “extinction-level event” may cause your composting process to stall.
You may want the ants gone right away, but there are a lot of insects inside, too, that you want to stay! Even so, sometimes you have to make the choice to save your compost.
There are a variety of pesticides available, but you should pick one that is appropriate for use on plants and crops and isn’t harmful to or transmissible through them.
You don’t want to end up with poison in your compost that could make its way into your next home-grown meal!
If you’re looking for something which has been properly evaluated for the purpose, the best option would is any pesticide that’s safe for vegetable farming. Pyrethrin or carbaryl are two such common pesticides that work well.
Consider carbaryl if you want to get rid of a serious ant infestation. Carbaryl is highly toxic to humans and other animals, but it does not accumulate in fat or other bodily fluids, and is rapidly eliminated from the body over time.
Full disclosure: It’s classified as a probable human carcinogen. Scary stuff, so use with maximum care.
Pyrethrin is another choice that’s a lot safer but nearly as effective. It is readily biodegradable and breaks down in the presence of strong sunlight.
If you decide to repeat an application of pyrethrin on your compost bin, you can take comfort knowing it won’t continually build up in the soil and other matter over time.
Hear me out, reader: When it comes to applying pesticides, especially to anything in your food chain, the most crucial thing to remember is that you must be cautious.
Make sure to follow all instructions on the label and use rated protective equipment and application procedures to avoid harming yourself or your family.
2. Add Diatomaceous Earth
Adding diatomaceous earth directly to the compost is a proven method of ant control for compost bins or piles.
Being white in hue and having a similar texture to pumice powder or clumped baking soda, this natural ingredient resembles nothing like the “earth” in its name.
Turns out it is actually made from the fossilized remnants of diatoms, a kind of microscopic algae. Whatever it is made from, all I know is this stuff kills ants real good.
Diatomaceous earth is abrasive and also absorbent, killing insects with an ingenious one-two punch: it first strips the outer, waxy layers of an insect’s shell away and then draws their bodily juices out.
Despite the fact that their carapace, or shell, is durable enough to endure the abrasion, once they lose that outer coating they cannot retain any moisture, meaning they will desiccate and perish.
Despite its effectiveness, believe it or not, diatomaceous earth is completely non-toxic and all-natural.
I like it because it is ruthlessly effective against insects, and that includes ants, but being all-natural and safe for use in your compost is great, too. Definitely, a terrible way to go if you are an ant, though…
Diatomaceous earth has been used in this manner against all kinds of pests for a long time, and it remains extensively utilized today for insect control in various agricultural settings, like grain storage.
Rest assured it will work like a charm in your compost pile. Toss in a few scoops, turn it over a few times, and you shouldn’t have to worry about ants in your compost bin for long.
Unfortunately, while it has many advantages, this stuff kills almost all insects and arthropods, not just ants alone.
That means there are a lot of beneficial critters establishing residence in your compost bin that will perish along with the ants.
Though it is natural and safe for people and animals, it is still an all-or-nothing option. Maybe save it for the worst infestations in compost that is nearly ready to use.
3. Introduce Parasitic Nematodes
Sometimes, the best way to deal with a natural pest is to let nature handle it. How? Turn one pest against another! In this case, parasitic nematodes. What exactly is a parasitic nematode?
Although it may seem like a gross monster your son made up, these things are entirely real, and unfortunately for the ants, it seems!
Parasitic nematodes are tiny, microscopic worms that infest and subsequently destroy ants.
Worse yet for the invaders, the ants have no defense against them because they are so small. These creatures can be found at any well-stocked garden supply shop.
You may introduce them in your compost bin ahead of time to prevent ant problems or eradicate an existing infestation.
Parasitic nematodes can be added to your compost pile in late spring or early summer, or anytime if you benefit from year-round warm weather.
Aside from being highly effective at controlling ant populations and collapsing their colonies, these parasitic nematodes aren’t dangerous to you, your plants (later), or any pets, so you don’t have to be concerned about negative side effects.
Consider this an all-natural, if somewhat gross, option.
4. Use a Moat
Though it will not assist you against a quickly spreading infestation that is already in your compost container, one simple and you might say “medieval” method to keep ants out is to surround your pile or bin with a moat.
Ants are unable to swim and will always drown or be carried away in any quantity of standing water.
If you fill a hollow ring or shallow trench with just a few inches of water, you can be certain that ants will not be able to cross it unless they are extremely lucky.
This is one of the safest and most effective strategies for keeping ants out of your bin, preventing problems before they start.
However, this is one defensive measure you’ll have to stay on top of. You must keep the moat filled with water or it will not function at all, and any object that forms a bridge over the obstacle will quickly be used by any questing ants.
But, when used in combination with other, natural ant control techniques, this is an ecologically friendly approach to keep ants at bay without harming or displacing the beneficial life forms within the compost.
5. Try Natural Ant Repellents
Ants dislike a variety of natural things, ranging from plants and oils to other naturally occurring chemicals.
Whether they are themselves irritated or harmed by them directly, or these substances merely disrupt their scent-based efforts at organizing and communicating, we don’t know.
All you need to know is that there is plenty of evidence that suggests that they do, definitively, work. Even better, you likely have a few of these all-natural deterrents in your home and kitchen already.
Sage, thyme, spearmint, peppermint, wood ash, and crushed eggshells are all examples of environmentally friendly “agents” that show effectiveness against ants.
Any of these may be ground into a fine powder or dried into fine flakes and sprinkled on the ground or inside the container to form a sort of barrier.
It’s also possible to add wood ash, eggshells, spearmint, or peppermint straight to your compost before turning it to distribute the repellent throughout the pile.
Even better, you may use any or all of them without the worry of harming beneficial “residents” such as earthworms or other insects that are breaking down organic matter in the pile.
6. Cover-Up Food Scraps
Food scraps from your kitchen are great for your compost pile, but they may also be the main attraction for any ants you’re attempting to eliminate.
Ants have strong olfactory senses and can both detect and home in on food from surprisingly long distances.
If even a single ant finds a food source, he will quickly return home and lead others back to it. Before you know it, you have an infestation.
When you put food waste on top of your compost heap without turning it, you are advertising to ants (among other pests) in the area where their dinner is served.
If you bury food waste in the compost bin, however, it will be more difficult for ants to find it and less likely that they will summon others to help them bring it home.
To further mask the presence of the buried food scraps and hopefully prevent ants from detecting it at all, add a layer of non-edible plant material on top of grass clippings, leaves, mulch, etc.
This is another excellent step to utilize in conjunction with other low-impact approaches.
7. Seal or Cover Your Bin or Pile
This is a basic defensive measure: If you have a nice, tight lid on your compost bin, ants will find it more difficult to get in.
This is especially true if the lid fits tightly, and has no cracks or holes in it that they are able to sneak through. When even a single ant is able to get in and back out, it is possible that he will lead an army of his relatives to the exact same spot.
A properly sealed container will aid with moisture retention, which is good for your compost and also a protective measure against ants, as we will discuss in a moment.
It’s possible to make a secure, almost gasket seal by retrofitting an existing lid with weather stripping, tape, or even caulk to create a firm, nearly gasket fit.
Because ants are tiny and can slip through the tiniest holes, this is a required step. So long as you are diligent, ants will have a hard time getting in.
Another disadvantage is that, if sealed too tightly without adequate ventilation, your lid won’t allow enough evaporation of moisture. This can lead to mold, slime, and other problems.
That being said, ventilation is easily accommodated by drilling some holes in an existing lid and then lining the inside with fine mesh or screen. Let the air out, and keep the ants out, that is the task.
8. Keep Compost Damp
This is another composting step that you should be doing as just another chore. If the compost is too dry, ants may be attracted to it as a worthwhile colony site.
You can avoid this by maintaining proper moisture levels in your compost bin. This means adding water regularly but making sure that the bin is also well-aerated so that excess moisture can evaporate and escape.
If you do this, ants will be less likely to see your compost as a potential colony site, and will likely avoid establishing themselves in your compost.
To be clear, though ants do require some moisture to survive, they prefer to tunnel in dry dirt.
Moist soil and other materials generally prevent them from easily making the tunnels that connect the colony and allow them a productive, safe home.
If your compost is allowed to dry, the ants are more likely to quickly establish a colony for reproduction. And believe me, they reproduce rapidly!
The right level of moisture in your compost bin to keep most species of ant at bay (and speed up decomposition) is going to be pretty moist.
To test it, if you try to compact a handful of compost into a ball or clump in your hands, one about the size of an apple, it should mostly stay together without squishing or falling apart.
If the compost is somewhat sticky to touch you’ll know that most ants will have difficulties excavating it and tunneling through it, and are less likely to set up a home base.
9. Turn the Pile
Turning your compost is something you should be doing anyhow, but I include it here because it is not only necessary for the overall health and production of the compost, but also for reducing insect infestation.
This accomplishes two goals. First, by aerating the compost, it increases decomposition speed.
Second, and more significantly for our goal, it collapses and tunnels any egg chambers that the ants may have established in the bin. This naturally upsets the ants, forcing them to move.
Turning is another method that you should use in combination with the others on this list, as it will prove even better when used as part of a process to keep the little critters out.
Even if you don’t want to add any chemicals or other compounds to your compost when you begin, simply turning it once a week will go a long way toward disrupting the ants before they develop a large colony – and also speeding up decomposition!
Take Back Control of Your Compost
There are many ways you can control ants in your compost, before or after they establish themselves.
From the natural to the decidedly modern, you should be able to discover a method or combination of methods that works best for you after a little experimentation.
Don’t let ants rob you of the hard work you have put into your compost; take action and take back control!
Tom has lived and worked on farms and homesteads from the Carolinas to Kentucky and beyond. He is passionate about helping people prepare for tough times by embracing lifestyles of self-sufficiency.