What Is Diatomaceous Earth?

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Diatomaceous earth can be used for everything from deodorizers to tick and flea powder. Its loyal fans find many more uses than that.

Diatoms, the main ingredient in diatomaceous earth (DE), may be the most useful things you’ve never heard of. They’re the odd, geometric-shaped amoebas or phytoplankton found in water when you look at it through a microscope. They help create the oxygen we breathe. They’re also found in many household products that contain silica.

Who Discovered Diatomaceous Earth?

The ancient Greeks first used DE as a building material for bricks, and its uses have multiplied throughout history.

These tiny one-celled life forms exist at the bottom of the food chain, using photosynthesis to turn carbon dioxide and water into food and oxygen. When they die, they become part of the muddy bottom of lakes and rivers. The National Science Teachers Association says a scoop of mud can contain 50 million diatoms. Their tiny shells preserve events in natural history that can be unlocked by science.

Diatomaceous Earth Uses

Caution: Be aware that some forms of DE can be dangerous if even small amounts are inhaled into the lungs.

All-purpose DE

When calcinated (exposed to high heat) the silica content in DE can be as high as 60 percent, making it suitable for use in filters.

For pest control, this so-called all-purpose DE can be used in powdered or wet form to reduce nuisance pests such as slugs, worms, spiders, aphids and ticks. When insects crawl through the substance — in gardens or along foundations, in cracks or at the perimeter of lawns — it damages their exoskeletons. They become dehydrated and die.

Other uses include:

  • As an abrasive for polishing things, like tarnished copper and flatware and stainless steel sinks;
  • As an absorbent, spread spills in the garage and such to make clean-up easier;
  • DE bath mats that are said to dry faster than all-cloth mats.

Food-grade DE

When food-grade DE is refined through a process of heating and filtering, the larger particles are removed, reducing its natural composition to about two percent silica. Some claim this kind of DE is safe to consume (about a teaspoon a day, in water) as a natural digestive aid. Food-grade DE is also used for:

  • Deodorizing the refrigerator;
  • Removing stains from clothes;
  • De-worming chickens;
  • Preventing weevils and moisture when mixed in dry goods, like grains;
  • Reducing fleas on pets;
  • Growing stronger fingernails and hair when mixed with water, as an elixir. One scientific study found consuming DE significantly reduced the cholesterol level of test subjects. But such uses should be approached cautiously and with the advice of a physician.

Where to Buy Diatomaceous Earth

Powdered forms of DE can be purchased by the bag at garden centers, large retail stores and online. All-purpose DE costs less than $20 for four lbs. and food-grade DE costs around $27 for 10 lbs.

Alison O'Leary
Alison O'Leary is a journalist, author, and public speaker with a wide range of writing experience: from multisport racing to home improvement to municipal government to fashion. She has been both freelance contributor and editor, has managed editorial budgets, hired contributors and reliably met deadlines. Alison's writing has been recognized not only in reader responses and advertising dollars but by journalism professionals from Parenting Publications of America, Florida Magazine Association, and New England Press Association awards.