• Diatomaceous Earth has to come in contact with pests for it to actually work.
• DE is a general pesticide, meaning it can kill healthy pollinators and other beneficial insects if used haphazardly.
• You’ll have to reapply DE after watering your plants or experiencing rainfall.

If you’re after organic methods of pest control, using diatomaceous earth should be at the top of your list.

Among its many benefits, diatomaceous earth (DE) can control pests as varied as earwigs, caterpillars, ants and aphids, and keep slugs and snails out of garden beds, too.

If you want to get the most benefits from DE, read on and learn how to use diatomaceous earth in the garden. We offer simple application tips for vegetables, herbs, ornamentals, and houseplants.

What Is Diatomaceous Earth?

The pest deterrent is actually made of fossilized marine organisms, so it’s an all-natural pest product approved for organic gardens—plus, it can reduce the need for chemical pesticides.

If you open a bag of diatomaceous earth, you’ll find a fine, white powder that closely resembles talcum.

DE is used in a lot of ways today—you can actually find it in toothpaste, skincare products, and even some foods and beverages. However, one of the main uses for diatomaceous earth is for garden pest control.

How Diatomaceous Earth Works in the Garden

To be effective, DE must come in direct contact with pests—but once it does, it works fast. It might feel soft to human fingers, but it’s incredibly sharp and shreds the exoskeletons of insects that touch it directly.

This causes insects to dry out, killing pests like cockroaches, flea beetles, bed bugs, and spider mites in less than 24 hours.

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How to Use Diatomaceous Earth

Be mindful when using DE: it’s a generalized pesticide that can kill most insects, including pollinators and beneficial bugs, so always use careful and targeted applications. Never apply DE to flowers or plants that pollinators visit often.

1. As a pest barrier in gardens: Simply sprinkle a light layer of DE in an unbroken circle or line on the soil around individual plants or along the exterior of garden beds using a DE applicator or duster.
2. As a barrier against household pests: DE can also be sprinkled around door and window frames to keep pests (like ants) from getting inside homes, garages, and potting sheds. Just be sure to apply the product when pets and children aren’t around and follow the manufacturer’s application instructions for safety.
3. To treat garden pest infestations: DE works well as a pest-repelling barrier, but it can also be sprinkled directly on plant leaves to treat active infestations of pests. Use a light touch when applying DE to plants—too much dust can make it hard for plants to photosynthesize.
4. To treat houseplant pests: If your houseplants have come down with a bad case of thrips, spider mites, or other pests, you can lightly them with DE. Use a mask when applying DE and move plants outdoors when dusting them to keep the DE from spreading around your home.

The Best Way to Apply Diatomaceous Earth

Diatomaceous earth can be applied by hand, but you’ll get more precise results if you use a DE applicator. Most often, DE is applied as a dry powder, but you can also mix it with water and apply it with a sprayer to hard-to-reach spots, like the undersides of plant leaves. DE is only effective when dry; wet applications will start working against pests as soon as the extra moisture evaporates.

To apply…

1. Create a ring of DE around plants. Spread DE in an unbroken ring around the plants, or lightly sprinkle or spray plant leaves with wet or dry applications during dry weather with minimal wind.
2. Spread in light layers. For best results, spread DE in light layers around plants and only lightly dust leaves so they can still absorb sunlight. Apply DE directly to areas where you know pests are active and likely to walk through the DE dust.
3. Reapply after watering or rainfall. As heavy rains can wash DE away, reapply after rainy weather. Apply DE several times throughout the season to keep pests at bay.

Note that DE works against a wide range of adult and larval insects, but it isn’t effective against insect eggs. Reapplying DE will ensure you treat for current and future generations of pests.