Does Diatomaceous Earth Kill Ants? An Expert Explains

Ants are pests in the home, especially in the kitchen. Outdoors, they contribute to crop damage by creating a breeding ground for pests such as aphids and whiteflies.

While toxic pesticides are effective, consider using diatomaceous earth as an organic, non-toxic alternative to killing ants.

Diatomaceous earth kills ants by drying and abrading their bodies. It is non-toxic, so it is safe to use indoors, although some precautions must be taken. Find out everything you need to know below.

What is Diatomaceous Earth (DE)?

Diatomite, or DE, is a naturally occurring soft silica sedimentary rock, according to entomologist David Price. The crushed version, often sold in gardening stores as a pest repellant, kills pests by decomposing and drying out their outer shells.

Diatomaceous earth is used to kill ants both indoors and outdoors. Since it is non-toxic, it is ideal for use indoors, especially around pets and children.

Types of diatomaceous earth

• DE Insect Control: Also known as insecticidal or vermin-killing diatomaceous earth, this product is effective against ants, bedbugs, fleas, and many other insects. It is also used to kill slugs and snails.
• Food grade DE: Food grade diatomaceous earth can kill ants, but this is not a recommended use. Food grade DE is often added to foods to prevent caking or used for health benefits.
• DE filter level: Sometimes referred to as pool grade DE, filter grade DE removes dirt, algae, and bacteria from pool water. It should never be used to kill ants as it may contain harmful additives.

How diatomaceous earth kills ants

Diatomaceous earth kills ants primarily by desiccation (causing the ants to wither) and secondarily by abrasion. Diatomaceous earth is not a toxic ant killer like commonly used pesticides, which attack the nervous system of insects.

How to kill ants with diatomaceous earth

To kill ants with diatomaceous earth, you will need:

• A bag of insect grade diatomaceous earth
• Diatomite powder spraying machine
• Vacuum cleaner shop
• Sponge and mild soap
• Dust mask and gloves

To kill ants:

1. Find food sources: Discover the source of the attraction—usually food. The ant trail will lead you to the source.
2. Delete source: Completely remove food source and wipe clean. Sugary foods may require additional cleaning with warm water and soap.
3. Remove live ants: Vacuum up ants indoors and outdoors. Cleans up live ants but leaves ant traces in place.
4. Add DE to the outside: Sprinkle diatomaceous earth outside the house, near where the ants are entering.
5. Add DE inside: Sprinkle diatomaceous earth inside the house, near entry points such as baseboards. Wear a mask to avoid inhaling DE.

DE Clean after application

Once the diatomaceous earth has killed the ants, clean the area with specialized cleaning products to ensure the ants do not return.

“Once the ants are under control,” says Price, “clean up the diatomaceous earth and dead ants. Wipe down areas where the ants have been using a cleaning product containing isopropanol amine, ammonium hydroxide, and a surfactant.”

1. Wait for the ants to die: Let the ants continue to move until they die. This usually takes 48 hours but can take up to 72 hours.
2. Remove dead ants and DE: Vacuum up dead ants and remaining DE. Wear a dust mask.
3. Clean the ant trail: Remove ant traces with warm water and mild soap (both indoors and outdoors).
4. Insertion point of the adhesive: Apply exterior grade silicone sealant to exterior points. Inside, apply painter’s grade silicone sealant around baseboards and trim.
5. Set up bait stations: Add ant bait stations near previous entry points.

Safety Considerations

Diatomaceous earth is non-toxic, but care must be taken during and after use:

• Use the right type of diatomaceous earth.
• Wear dust mask, eye protection, gloves and long sleeves.
• Keep pets and children away when using DE.
• Avoid areas where DE may be blown away: near doors, fans, ventilation ducts, air conditioner or air handler returns.
• If possible, avoid placing DE in high traffic areas.

Tips for using DE to kill ants

• The purpose is direct contact: Ants must walk through DE; close proximity will have no effect. To be effective, ants must come into direct contact with the substance, so proper application to infested areas is important, says Dr. Allen.
• Avoid large landfills: Pouring a large amount of powder onto the kitchen counter will not be effective – the ants will likely stay away from the powder.
• Apply gently:According to Price, it doesn’t take much diatomaceous earth to do this.
• Start from the outside, not the inside:While you can start with ants inside your home, start by building a barrier around the outside. Price suggests spreading diatomaceous earth outside around the perimeter of your home’s foundation since ants are coming in from the outside.

When not to use DE

Diatomaceous earth is not always the best solution for killing ants. Large infestations, the need for quick extermination, and humidity are just a few reasons to use different methods.

“If you need immediate control or have a kitchen full of ants, avoid using diatomaceous earth,” says Dr. Allen. “It takes time to work and is most effective when used sparingly.”

Diatomaceous earth works best in dry conditions, Price says. Moisture is the enemy of diatomaceous earth, as it can clump and ants won’t have direct access to it to attach to their bodies.

Do not apply in wet areas indoors or outdoors when rain is forecast. For exterior applications, it is best to wait 24 hours after rain to allow the area to dry.