Diatomaceous earth and how to use it
By Judy Allen, Denton County Master Gardener Association
Sep 28, 2023
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What is diatomaceous earth?

What is diatomaceous earth anyway? It is the fossilized remains of tiny aquatic organisms called diatoms. Over thousands of years, diatoms accumulated in rivers and lakes and decomposed in the sediment. These diatoms are made of silica, which is mined and used for many different purposes. Today, our focus is on the benefits of diatomaceous earth (DE) and its uses.

Environmentally safe

When using DE in the garden, it is important to purchase horticultural or ďfood gradeĒ. This is a non-toxic environmentally friendly substance. A certain kind of DE is used in the maintenance of swimming pools. This is NOT the diatomaceous earth that you want to use. It has been processed and has added ingredients that can make it toxic. Keep in mind that DE is a powder, very similar to talcum powder. Donít inhale it. Wear a mask and gloves as you find it necessary. It is not harmful to pets or fish, but it is dusty to say the least. DE is used to help control fleas, slugs, ants, mites, spiders, and various soft bodied insects. Many chicken keepers keep a tray of horticultural DE in the pen for the chickens to use as a dust bath. A great mite control.

How does it work?

How does it work? Even though we canít feel anything except the soft powder, it has jagged edges that affect soft bodied insects. They crawl over it, and it cuts into their exoskeletons. It also has a drying effect and is absorbed into the bugís breathing tubes or joints. The insects donít need to consume it, just walk over it.

Non-toxic pest control

Diatomaceous earth is a cheap non-toxic pest control. It can be used in your home, in the back of cupboards, and around baseboards. Place around the perimeter of your home as an insect deterrent. Remember to reapply it if it gets wet. This can be a safe way to fight those annoying little pests.

Ants in the garden

I find DE particularly effective at chasing away ants, including fire ants. When Iím in the garden and encounter an ant pile, I grab the DE. One scoop of dry product sprinkled on the pile and within minutes they are gone. It only works when dry so using it on a rainy day wonít really work. It does regain its effectiveness once dry. The extension and university resources that I researched, stated that DE does not effectively kill the fire ant colony. So, I guess they go somewhere else, but thatís alright with me, since they are now out of my work area. Thereís nothing worse than trying to work around ants!

As a side note, since I live in the country, I buy diatomaceous earth by the 50-pound bag. Along with using it in the garden, I spread it in the pasture where fire ant mounds appear. I am sure the cows appreciate it. HA. The large bags are readily available at animal feed and supply stores.

Insect Management Resources.
https://texashelp.tamu.edu/wp-content/uploads/2016/02/managing-imported-fire-ants-in-urban-areas-1.pdf

Insect Control https://www.gardeningknowhow.com/plant-problems/pests/pesticides/diatomaceous-earth-insect-control.htm

https://extension.umn.edu/yard-and-garden-news/what-diatomaceous-earth

Happy Gardening!

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