Does Diatomaceous Earth Kill Ants? [5 Ways to Use it Right]

Diatomaceous earth is one of the safest and most effective ant killers you can buy. It is an all-natural product made from fossilized single-celled algae. Ants that walk through diatomaceous earth will be killed as the powder damages the ants’ exoskeleton and dehydrates the ant until it dies. You can spread diatomaceous earth both indoors and outdoors to kill ants without using any chemicals that risk the health of your family or pets.

What is Diatomaceous Earth?

Diatomaceous earth is simply the fossilized remains of single-celled organisms called diatoms. It resembles a fine dust or powder. Because it is simply fossils, diatomaceous earth contains no chemicals or insecticides. Horticultural grade diatomaceous earth is safe for humans and non-insect animals.

How Does Diatomaceous Earth Kill Ants?

The prevailing theory is that diatomaceous earth kills ants by making tiny cuts in the ant’s exoskeleton. These tiny cuts then allow the diatomaceous earth to soak up fluids inside the ant, drying out the ant and killing it. The tiny fossils are too small to harm humans, but walking on diatomaceous earth is like walking on broken glass for ants.

• The most common theory is that diatomaceous earth cuts ant exoskeletons and dries out the ants.
• Another theory is that diatomaceous earth blocks the respiration of ants and suffocates them.

There are other theories about how diatomaceous earth kills ants. The small powder particles may in fact clog the respiratory pores in ants, suffocating and killing them. Either way, diatomaceous earth is an extremely effective ant control method, often better than methods like boiling water, that doesn’t contain any chemical pesticides.

Do Ants Take Diatomaceous Earth Back to the Nest?

Unlike poisoned ant baits, ants do not carry diatomaceous earth back to the nest. In fact, they don’t see diatomaceous earth as food at all. Ants die simply from walking through diatomaceous earth. So, whether the ant is hungry or not, it will be killed simply by setting foot in this fossil powder.

Will Diatomaceous Earth Kill the Queen Ant?

Diatomaceous earth will not kill the queen ant directly. Queen ants do not typically leave the nest, which means they are not likely to walk through diatomaceous earth. However, spreading diatomaceous earth around an ant mound will kill every ant that leaves the mound. When the workers are killed by walking through diatomaceous earth, they can’t feed their queen. So, if you kill the worker ants by spreading diatomaceous earth, the queen ant will starve and die.

5 Ways to Use Diatomaceous Earth to Kill Ants

Whenever you are using diatomaceous earth to kill ants, make sure to use a horticultural grade of diatomaceous earth or this food grade diatomaceous earth. Other types of diatomaceous earth are not safe for people and animals, but a food-grade product will kill ants without harming your family, pets, or lawn. Here’s how to use it:

Spread it on Ant Trails

If you have spotted trails where trains of ants are traveling back and forth in your home or yard, spread a dusting of diatomaceous earth along these trails. Ants travel the same trail repeatedly due to the pheromone scents left by other ants. If you spread diatomaceous earth along an established ant trail, you’ll kill all the ants who travel along it.

Protect Windows and Baseboards

Ants commonly invade the home by entering around windows or where the baseboard meets the wall. If you have an ant invasion and can’t seem to find the source, start by spreading diatomaceous earth on window sills and along the baseboards in your house. If you’ve chosen the right place, you’ll begin seeing dead ants among the diatomaceous earth. Then, you can simply vacuum up the excess diatomaceous earth.

In the Kitchen

Ants commonly invade cupboards in search of food. To keep ants at bay in the kitchen, dust kitchen shelves and the backs of cupboards with diatomaceous earth. This way, any ants that sneak into your pantry will be killed before they reach the food.

Around Ant Mounds

Spreading diatomaceous earth is one of the best ways to get rid of ant colonies in your yard. Spread diatomaceous earth in a generous ring around all the individual mounds that you see. This ring will kill any ants that exit the mound. If the worker ants can’t leave to gather food, the entire colony will starve and die.

Create a Perimeter Around Your House

In order to completely prevent ants from entering your home, spread a trail of diatomaceous earth in a ring around your home. It’s best to start this ring 16–24 inches (40–60 cm) from your foundation. Always spread diatomaceous earth in dry weather, since it is not effective when wet. Also, keep in mind that mowing and other lawn care will blow away your protective ring of fossilized diatoms.

How Often Should You Apply Diatomaceous Earth to Kill Ants?

Reapply diatomaceous earth every 1–2 months indoors and every 1–2 weeks outdoors. Diatomaceous earth outdoors can be blown away by wind or washed away by rain. If you spread it around ant mounds and it’s rained since then, it’s time to reapply. However, it’s best to wait until conditions are dry again. Diatomaceous earth is useless when wet, but will kill ants effectively when it’s dry.

• Reapply diatomaceous earth outdoors every 1–2 weeks.
• Indoor diatomaceous earth treatments should be replenished every 1–2 months.
• Wind and rain disperse diatomaceous earth, so it’s best to reapply after rainfall or windy conditions.
• Do not spread diatomaceous earth in wet conditions—it’s only useful for killing ants when it’s dry.
• Diatomaceous earth indoors should be vacuumed up periodically to remove dead ants.

Because the inside of your home is not exposed to weather and rain, diatomaceous earth can remain useful for months along your baseboard, window sills, or in your cupboards. However, it’s a good idea to vacuum up the powder once every few weeks. This will remove dead ants and old powder. Then, simply reapply your diatomaceous earth.

How Long Does it Take Diatomaceous Earth to Kill Ants?

It will take 16–24 hours before diatomaceous earth begins to kill ants. The ants will slowly be killed by walking through the powder along trails, around ant mounds, or in your cupboards. So, while diatomaceous earth doesn’t work instantly, it will provide results in about 1 day.

Can You Mix Diatomaceous Earth With Water and Spray It?

You can make a diatomaceous earth spray by combining 1 tablespoon (15 ml) of diatomaceous earth powder with 4 cups (1 liter) of water. Then, you can use a spray bottle to spray the mixture onto whatever surface you choose. Once the mixture dries, the diatomaceous earth will begin killing any ants that walk through it.

Does Diatomaceous Earth Kill Ants Instantly?

Diatomaceous earth does not kill ants on contact, but it will begin killing ants within 16–24 hours after spreading it. To use diatomaceous earth indoors and outside, use the following methods:

• Spread diatomaceous earth on active ant trails.
• Dust window sills and baseboards with diatomaceous earth to stop invading ants.
• Use diatomaceous earth in your kitchen cupboard to kill food-raiding ants.
• Spread diatomaceous earth in a circle around ant mounds in your yard.
• Create a perimeter of diatomaceous earth around your house to stop ants from entering.

These simple preventative measures will kill ants of all kinds. Plus, you’ll do so without risking your own health. Diatomaceous earth is made from the fossils of aquatic organisms, so it’s harmless to your yard, your family, and animals. It’s an amazing tool for killing ants the organic way.