In my years of battling pests, I’ve found diatomaceous earth (DE) to be a game-changer. This fine white powder is nature’s secret weapon against insects with exoskeletons. It works by physically damaging their protective coverings, leading to dehydration.

I’ve seen DE effectively prevent pests in gardens, homes, and everywhere in between. It’s a versatile tool that, when used right, can be your first line of defense against unwanted creepy crawlies.

What is Diatomaceous Earth?

Diatomaceous earth is created from the fossilized remains of phytoplankton, an ancient aquatic microorganism.

DE can be found naturally in sedimentary rocks and is mined for use in a variety of products, such as organic insecticides, cosmetics, toothpaste, swimming pool filters, industrial products, pharmaceuticals, and food products. Visually, diatomaceous earth is a fine white powder that feels smooth to the touch.

Food grade diatomaceous earth is non-toxic to fish, birds, aquatic invertebrates, and other wildlife, making it a safer pesticide option for wildlife than traditional pesticides.  In contrast, industrial-grade diatomaceous earth has a stronger silica concentration, making it toxic to some mammals.

diatomaceous earth powder on a surface close-up
Image Source: Canva

What Pests Does Diatomaceous Earth Kill?

Diatomaceous earth works by piercing the exoskeleton of insects. The diatoms, or phytoplankton, that make up DE have tiny, strong shells made of silica, one of the hardest natural substances on Earth. The sharp edges of the silica cause hundreds of abrasions on insects with exoskeletons, causing irreparable damage. Once the insects’ exoskeletons are pierced, they dry out and pass away.

As a result, you can use diatomaceous earth against any insects with exoskeletons, such as roaches, crickets, or centipedes.

Diatomaceous earth kills a huge variety of pests, including:

  • Bed bugs
  • Cockroaches
  • Slugs*
  • Centipedes
  • Millipedes
  • Snails*
  • Crickets
  • Moths
  • Fleas
  • Lice
  • Beetles
  • Sow bugs
  • Pill bugs
  • Twig borers
  • Mites
  • Thrips
  • Ants
  • Termites
  • Armyworms
  • Fungus gnat larvae
  • Aphids
  • Ticks
  • Fruit flies
  • Spiders
  • Silverfish
  • Earwigs

*DE does not kill directly Snails and slugs, but it’s a huge deterrent for them because it’s uncomfortable for them to crawl over, and it slows them down. As a result, you can use DE as a deterrent or barrier against slugs and snails.

For diatomaceous earth to work, it has to come into direct contact with the insect or critters. As a result, pollinators, ladybugs, and other beneficial insects are typically safe if DE is only applied on the ground and not near flowers or plants frequented by pollinators.

If bees or other beneficial insects come into contact with DE, it will pierce their exoskeletons, killing them, so keep this in mind when placing DE in your backyard.

Diatomaceous earth does not affect certain insects, like caterpillars and earthworms, because of their thick outer mucus layers, which aid them when they travel through gritty soil. As a result, you can safely use DE in a worm compost bin.

Is Diatomaceous Earth Dangerous to Humans?

Diatomaceous earth is considered safe for use around mammals, wildlife, and humans because it’s pure silicon dioxide, which is non-toxic and found in many items at your local grocery store. For example, DE can be found in makeup, pool filters, grain storage products, and filters for alcohol.

However, when applying DE, you must wear a dust mask because inhaling DE is unhealthy for animals and humans. The fine dust particles may cause respiratory issues, especially after long-term exposure. You’ll also want to be extremely careful not to get diatomaceous earth in your eyes because it could scratch your cornea.

How to Apply Diatomaceous Earth

The simplest way to use DE in your garden is to sprinkle it on the soil’s surface, under potted plants, and anywhere else you spot pests. Avoid applying diatomaceous earth too close to flowering plants that pollinators visit because DE can kill these beneficial insects. Also, don’t dust DE directly onto plants, as this will harm bees and pollinators.

The best time of day to apply diatomaceous earth is during the evening, when pollinators are less active. You’ll also want to wait to use food-grade DE until the wind dies down so the powder doesn’t spread.

Lastly, keep in mind that diatomaceous earth is rendered almost ineffective when it gets wet. As a result, wait until plants and soil are dry to sprinkle DE on top. Don’t apply DE immediately after it rains or you’ve watered your plants, as this is a waste of product. Typically, you’ll want to use diatomaceous earth weekly until the pest infestation is under control.

applying diatomaceous earth on soil
Image Source: Canva

What Happens to Diatomaceous Earth in the Environment?

DE is generally considered to be environmentally friendly due to its natural origin and non-toxic nature. When applied outdoors, diatomaceous earth eventually breaks down and becomes part of the soil.

In the environment, DE behaves much like naturally occurring silica or sand. It doesn’t chemically react with other substances or leave harmful residues. Rain and wind will gradually disperse DE, integrating it into the surrounding soil. This process is entirely natural and doesn’t pose any significant environmental risks.

However, it’s important to note that while DE is safe for soil and water systems, its effectiveness as a pest control agent diminishes when it gets wet. This is why reapplication is often necessary after rain or heavy dew.

One environmental consideration to keep in mind is the potential impact on beneficial insects. As mentioned earlier in the article, DE can harm any insect with an exoskeleton that comes into direct contact with it. Therefore, careful application is crucial to minimize unintended effects on helpful garden inhabitants like ladybugs or ground beetles.

Overall, when used responsibly, diatomaceous earth is an environmentally sound choice for pest management that doesn’t contribute to long-term ecological harm.

Frequently Asked Questions

How does diatomaceous earth work?

Diatomaceous earth works through a physical mechanism. When insects with exoskeletons come into contact with DE, its microscopic sharp edges act like tiny shards of glass, scratching and cutting through the insect’s protective outer layer. This damage disrupts the waxy coating on the exoskeleton and creates openings through which moisture escapes, causing the insect to dehydrate and eventually die. This process is purely mechanical, which is why insects can’t develop resistance to DE as they might with chemical pesticides.


Is food-grade diatomaceous earth just a scam?

No, food-grade diatomaceous earth is not a scam. It’s a legitimate and effective pest control product. The term “food-grade” means it’s purified and safe for human consumption, meeting the standards set by the Food and Drug Administration (FDA). While its effectiveness as a dietary supplement is debated, its use in pest control is well-established. Food-grade DE is often preferred for household use because it’s safer around pets and children compared to chemical pesticides or industrial-grade DE.


Can diatomaceous earth effectively eliminate a cockroach infestation?

Diatomaceous earth can be an effective part of a cockroach control strategy, but it may not remove an infestation on its own. DE works well as a barrier treatment and can kill cockroaches that come into contact with it. However, cockroaches are resilient and often hide in hard-to-reach places. For best results, combine DE with other methods such as sealing entry points, removing food sources, and using baits or traps. Persistent application of DE in areas where cockroaches travel can significantly reduce their population over time.


How long does it take diatomaceous earth to kill bugs?

The time it takes for diatomaceous earth to kill bugs varies depending on the insect’s size and the environmental conditions. Generally, smaller insects may die within a few hours of contact with DE, while larger insects might take a few days. The process of dehydration isn’t instant. Insects need to come into contact with enough DE and then gradually lose moisture. In optimal conditions, you might see results within 24 to 72 hours, but it could take up to a week or more for larger infestations.


How do you use food grade diatomaceous earth to get rid of indoor fleas?

To use food-grade diatomaceous earth for indoor flea control:

  1. Vacuum thoroughly to remove as many fleas and eggs as possible.
  2. Sprinkle a thin layer of DE on carpets, rugs, and pet bedding. Use a brush to work it into the fibers.
  3. Apply DE to cracks and crevices in floors and baseboards.
  4. Leave the DE in place for at least 24–48 hours.
  5. Vacuum again to remove dead fleas and excess DE.
  6. Repeat the process every few days for several weeks to break the flea life cycle.

Remember to treat your pets with appropriate flea control products as well, as DE won’t affect fleas while they’re on your pet. Always wear a dust mask when applying DE to avoid inhaling the fine particles.


Final Thoughts

Diatomaceous earth is a simple, natural product that is great for insect control, especially if you’re concerned about using traditional pesticides that are not natural or organic in your garden. This organic pest control method is also typically safe for use around pets and children, making it an excellent alternative to typical pesticides.

Once the pest problem is under control, start taking measures to prevent pests from returning. Prevention is always easier than dealing with a pest infestation, so take steps to change your background environment, seal cracks and crevices where pests may be entering your home, and add plants that are natural deterrents to pests to your garden.

If all else fails, consult with a pest control professional to have your home treated and assessed for potential shortcomings attracting pests to your home and garden.

Article Update Log
6/20/2024
Reviewed for accuracy, cost data, industry best practices, and expert advice by Coty Perry.
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Sam Wasson

Staff Writer

Sam Wasson graduated from the University of Utah with a degree in Film and Media Arts with an Emphasis in Entertainment Arts and Engineering. Sam brings over four years of content writing and media production experience to the Today’s Homeowner content team. He specializes in the pest control, landscaping, and moving categories. Sam aims to answer homeowners’ difficult questions by providing well-researched, accurate, transparent, and entertaining content to Today’s Homeowner readers.

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Coty Perry

Expert Writer & Reviewer

Coty Perry is a lawn and garden writer for Today’s Homeowner. He focuses on providing homeowners with actionable tips that relate to the “Average Joe” who is looking to achieve a healthier and greener lawn. When he isn’t writing he can almost always be found coaching youth football or on some trail in Pennsylvania in search of the next greatest fishing hole.

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