A prominent, mouthful-of-a-name in the organic gardening community for organic pest control is Diatomaceous (dahy-uh-tuh-mey-shuhs) Earth. Found as both food grade and pool grade, it is the powdery remains of ancient algae. The two grades are the same substance, but pool grade is treated at high heat, which changes the make up slightly, and is not regulated for heavy metal content. Pool grade diatomaceous earth is not used for anything except pool filtration, so be cautious to purchase food grade only when using it for pest control.


Diatomaceous earth is not a chemical, and it is safe to use on your plants and produce. It is also safe to ingest; however, it can be dangerous if inhaled, so please be careful when applying it to your garden and using it in your home. Natural does not always mean innocuous. Exercise caution and be safe.

With that out of the way, there are pages and pages of information on the web about diatomaceous earth, and we’ve weeded through it to bring you what you need to know. Here is what some of our friends around the web have to share regarding their experiences with diatomaceous earth and their gained wisdom.

How Diatomaceous Earth Works

Because diatomaceous earth is more than just the powder it appears to be– it is crushed, fossilized remains – the actual particles are jagged and sharp. The idea is that it either scratches and damages the pests’ bodies and dries up their fluids, or it is absorbed into their breathing, eyes, etc. Ultimately, as this blog, focusing on diatomaceous earth for ant control, says – “I'm not sure I care about exactly how it works - just that the bugs quit eating and death isn't far behind.”

With this in mind, Jill from The Prairie Homestead shares helpful reminders in this guest post about the mechanics of diatomaceous earth. Since it is a physical reaction that the bugs have, they cannot build up an immunity to it like they can with chemical pesticides. Be careful, though, because diatomaceous earth is non-discriminatory. It will wipe out all bugs, beneficial or not!

Pros and Cons of Diatomaceous Earth

While a natural, non-toxic pest control remedy sounds like something to be revered, it has benefits and drawbacks like anything else. The inability to choose which bugs are affected by it is one big concern, and there are others.

Erica at Mom Prepares has some experience with diatomaceous earth, and she suggests using it as a preventative measure. Don’t expect it to be able to tackle a major infestation.

Our friends at Homestead Chronicles made their own bug spray as a companion to diatomaceous earth because it “isn’t for every bug every time.” In particular, it has to stay dry and powdery to be effective; rainwater and regular watering wash it right away.

When to Use Diatomaceous Earth

Because of the reaction it causes, diatomaceous earth is effective against anything with an exoskeleton. This includes just about every garden pest you can think of. Of course, it is not the only remedy for pests, and the Big Blog of Gardening reminds us that it should be used as a last resort, as with any pesticide. However, if you have exhausted your resources and still need to rid your garden of pests, make sure you wait until the weather is forecasted to be dry. Remember, you want the bugs and slugs to carry it off – not the rainwater!

Not just for the garden, diatomaceous earth can be effective for indoor pests, as well. Mother Earth News has this great piece on the ways you can utilize it around the homestead. From roach control in the home to lice control for chickens to flea control for pets, having a non-toxic, versatile pest control method like this can be quite handy.

Beyond the Vegetable Garden

Clean Coops has a detailed list of the ways they use diatomaceous earth. While water can wash away dusted diatomaceous earth, suspending it in water and using it in sprayers seems to be effective. They even paint it onto tree trunks to protect fruit trees!

Because it is non toxic, this Untrained Housewife article suggests using it everywhere, when necessary. It can be sprinkled over the yard, used in both vegetable and flower gardens, and even applied near where animals live and eat.