Updated: Jul 28
Besides being really hard to pronounce, what's so special about diatomaceous earth? Well, it actually has many uses in the garden and elsewhere. But first, let's talk about what it is.
Diatomaceous Earth (DE) is the fossilized remains of ancient water plants called Diatoms. They pile up on the seabed and over millions of years, create a soft sedimentary material that can be easily crushed into a flour-like powder. It is 100% natural Silicon Dioxide, a mineral compound containing 3% magnesium, 5% sodium, 2% iron, 19% calcium, and 33% silicon (and several other trace minerals).
Under a scanning electronic microscope it looks a lot like Chex Mix.
Choose Food Grade DE
DE can be ground down to different particle sizes depending on the specific use. Those tiny particles have microscopic sharp edges that give it an abrasive quality. Basically there is a "filter grade" used in swimming pools and other water filtration systems. And then there is a "food grade."
Marshall Grain Co. only sells food-grade DE, which is safe for humans and pets to consume.
Because it is slightly abrasive, food-grade DE also used in toothpastes, metal polishes, and many other household products and is even used as an additive in some foods. For instance, you can use it as a flea powder on your pets, apply it to your bedding to eliminate bedbugs, or treat your carpet with it.
Using Diatomaceous Earth As An Insecticide
Gardeners love to use food-grade DE as an organic insecticide. Since DE is non toxic, it is completely safe to use on your vegetable garden. Instead of poisoning insects, DE's naturally abrasive and moisture absorbing qualities work on any type of insect that has an exoskeleton by simultaneously scraping the exoskeleton and dehydrating the insect. When used dry, it works great all by itself on exoskeletal insects. It also works on insects that are easily dehydrated, such as aphids, slugs, snails and thrips.
Note: Because DE is a very fine dust, it is wise to wear a mask when applying or mixing it.
You can spread it on your lawn to kill many crawling insects such as cockroaches, ants, fleas, ticks, chiggers, beetles, and many other hard-shelled insects. Dust the foliage of your plants with it to kill aphids, thrips, mites, earwigs, beetles, and other clinging pests.
Be careful not to apply DE to beneficial insects like Ladybugs, Bees, or Wasps!
Two major advantages of DE are that, for one, insects can't build up a resistance to it as they generally do with poisons. Secondly, DE doesn't harm beneficial microorganisms in the soil, so your earthworms and microscopic flora and fauna will not be affected by it.
When using it as described above, the product will continue to work as long as it remains dry. Moisture causes it to cake. So, it will need to be reapplied after running your sprinklers or after a rain.
You Can Mix DE With Other Ingredients
DE is also often used as a carrier to help spread other insecticides. For example, Nature's Creation Fire Ant Killer is DE supplemented with Pyrethrin, which is an organic insecticide in it's own right.
When mixed with other ingredients, Diatomaceous Earth can also be liquefied ̶̶ for example, to treat fire mounds. Simply mix it in a bucket of water and pour the mixture onto the mound. The water carries the DE into the underground cavities where the abrasive particles destroy any ants they comes into contact with.
Marshall Grain Co. sells DE in several different size packages. We also carry Nature's Creation Fire Ant Insecticide and Perma-Guard, both of which are DE blended with other insecticides. We're always here to help you choose the best product for your needs.