By Amy DeYoung
Updated Nov 18, 2022
You may have heard about diatomaceous earth (DE) or seen a neighbor sprinkling a fine white powder onto the ground to fight garden pests. Diatomaceous earth is an effective, natural insect control product that works against insects with exoskeletons by piercing these protective coverings, causing them to dehydrate and die. When used correctly, it’s highly effective for pest management in a garden, houseplants, backyard, and more. You can even use food grade diatomaceous earth sprinkled along windowsills and by doors to kill pests as they try to enter your home.
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 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:
*Snails and slugs aren’t killed directly by DE, 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.
Certain insects, like caterpillars and earthworms, are not affected by diatomaceous earth 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.
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.
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. In addition, 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.
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’s 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.
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