Does Diatomaceous Earth Kill Ants? What a Pest Expert Recommends
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Ants are a nuisance indoors, especially in kitchens. Outdoors, they contribute to plant damage by enabling destructive insects like aphids and whiteflies.
While toxic insecticides are effective, consider using diatomaceous earth as an organic, non-toxic alternative for killing ants.
Diatomaceous earth kills ants by drying out and abrading their bodies. It is non-toxic, so it is safe to use in homes, though some precautions should be taken. Find out everything you need to know below.
Meet the Experts
Dr. Hamilton Allen is a board-certified entomologist with Fox Pest Control.
David Price is an entomologist and technical director at Mosquito Joe.
What Is Diatomaceous Earth (DE)?
Diatomaceous earth, or DE, is a naturally occurring, soft, siliceous sedimentary rock, according to entomologist David Price. The crushed version, often sold in gardening stores as a pest deterrent, kills them by breaking down and drying out their exoskeletons.
Diatomaceous earth is used to get rid of ants both indoors and outdoors. Since it's non-toxic, it's ideal for indoor use, especially where pets and kids are concerned.
Types of Diatomaceous Earth
Insect-control DE: Also called pest-control or insect-grade diatomaceous earth, this product kills ants, bedbugs, fleas, and many other insects. It is also used for killing slugs and snails.
Food-grade DE: Food-grade diatomaceous earth can kill ants, but this is not its recommended use. Food-grade DE is often added to food to prevent caking or is consumed for health benefits.
Filter-grade DE: Sometimes called pool-grade DE, filter-grade DE strains dust, algae, and bacteria from pool water. It should never be used to kill ants as it may contain harmful additives.
Pest Control Tip
Use insect-control diatomaceous earth to kill ants. Food-grade DE is not recommended for killing ants, and filter-grade DE should be avoided altogether.
How Diatomaceous Earth Kills Ants
Diatomaceous earth kills ants mainly through desiccation (drying out the ants) and secondarily with abrasion. Diatomaceous earth isn't a toxic ant killer, like the commonly used pesticides, which attack the insect's nervous system.
How to Kill Ants With Diatomaceous Earth
To kill ants with diatomaceous earth, you will need:
One bag of insect-grade diatomaceous earth
Diatomaceous earth powder duster
Shop vacuum
Sponge and mild soap
Dust mask and gloves
To kill the ants:
Find the food source: Discover the source of the attraction—typically, food. Ant trails will lead you to the source.
Remove the source: Remove the food source entirely and wipe it down. Sugary food may need additional cleaning with warm water and soap.
Remove the live ants: Vacuum up ants indoors and outdoors. Clean up the live ants but leave the ant trails in place for now.
Add DE to the outside: Dust diatomaceous earth on the outside of the house, near ant entry points.
Add DE to the inside: Dust diatomaceous earth on the inside of the house, near entry points like baseboards. Wear a mask to avoid breathing in the DE.
Cleaning Tip
Dispose of the vacuum bag or empty the canister, as ants can crawl out.
DE Post-Application Cleaning
Once the diatomaceous earth has killed the ants, wipe down the area with specific cleaning products to ensure that the ants do not return.
"Once the ants are under control," says Price, "clean up the diatomaceous earth and dead ants. Wipe down the areas where the ants were trailing with a cleaning product that contains isopropanol amine, ammonium hydroxide, and surfactants."
Wait for the ants to die: Let the ants continue traveling until they die off. This usually takes 48 hours but can take as long as 72 hours.
Remove dead ants and DE: Vacuum up the dead ants and the remaining DE. Wear a dust mask.
Clean the ant trails: Remove the ant trails with warm water and mild soap (both indoors and outdoors).
Caulk entry points: Apply exterior-grade silicone caulk to the outside extry points. Inside, add painter's grade caulk around baseboards and trim.
Place bait stations: Add ant bait stations near the former entry points.
Important Tip
Price emphasizes that the ant trails, though invisible, must be cleaned as they contain pheromones left by the removed ants. Pheromones encourage more ants to return, so removing the unseen trails stops future infestations.
Safety Considerations
Diatomaceous earth is non-toxic, but care should be taken during and after its application:
Use the right type of diatomaceous earth.
Wear a dust mask, eye protection, gloves, and long sleeves.
Keep pets and children away when applying the DE.
Avoid areas where the DE may blow away: near doors, fans, air ducts, A/C air returns, or air handlers.
Avoid placing DE in areas of heavy foot traffic, if possible.
Tips for Using DE to Kill Ants
Aim for direct contact: Ants must walk through the DE; close proximity will do nothing. To be effective, the ants must come in direct contact with the substance, so proper application to infested areas is key, says Dr. Allen,
Avoid large dumps: Pouring large amounts on your countertop will be ineffective—the ants will likely just avoid the powder.
Apply lightly: It doesn’t take much diatomaceous earth, to do the trick, according to Price,
Start outside, not inside: Though it's tempting to start with the indoor ants, begin by building an exterior perimeter barrier. Price suggests applying diatomaceous earth to the outdoors around the foundation perimeter of the home as ants are gaining access to the interior from the exterior.
When Not to Use DE
Diatomaceous earth isn't always the best solution for eliminating ants. Large-scale infestations, the need for quick extermination, and moisture are a few reasons to use different methods.
"If you require immediate control, or have a kitchen teeming with ants, avoid diatomaceous earth," Dr. Allen says. "The material takes time to work and is most effective when used sparingly."
Diatomaceous earth works best in dry conditions, Price says. Moisture is diatomaceous earth’s enemy, as it can clump and ants will not have direct access to attach to their bodies.
Do not apply in damp humid areas in the home, outside when rain is pending in the forecast. For an outside application, it is best to wait 24 hours after rain to let areas dry out.
Frequently Asked Questions
How long does it take to kill ants with diatomaceous earth?
It takes about 48 to 72 hours to kill ants with diatomaceous earth.
Can you mix diatomaceous earth with water and use it as a spray?
You can mix diatomaceous earth with water and use it as a spray, but it will kill ants, slugs, and other pests only after the slurry has dried out. So, the best way to apply diatomaceous earth is in dry powder form, broadcasting it lightly with a hand-held puffer-duster.
Is borax the same as diatomaceous earth?
Borax is not the same as diatomaceous earth (DE). Borax is a mineral, while diatomaceous earth consists of fossilized diatoms. However, both borax and diatomaceous earth will kill ants. Diatomaceous earth affects the outside of the ant, drying it out and abrading it to death. Borax is ingested by the ant and kills it from the inside out.
Read the original article on The Spruce.
