Why Every Indoor Gardener Needs Diatomaceous Earth


Diatomaceous Earth poured on table with spilled houseplant pot of soil

After a while of growing plants indoors, you start to find the supplies, products, and tools that work best for your unique indoor gardening needs. Diatomaceous earth should be on that list if it’s not already sitting on your gardening shelf. Never heard of diatomaceous earth before? If not, then you probably have some questions, starting with, what is diatomaceous earth or why you need it for your plants, or how to use it?

Why does every indoor gardener need diatomaceous earth? Diatomaceous earth is organic sedimentary rock powder that’s used to kill & ward off a slew of indoor garden pests including mites, ants, aphids, maggots, flies, and slugs, without any chemicals & while boosting porosity in pots & deodorizing your indoor plants.

In this article, I’ll talk much more about diatomaceous earth’s many benefits. Before that, I’ll get into what this powder really is and where it comes from. I’ll even explain how to use diatomaceous earth, so keep reading! You’re not going to want to miss it.

What Is Diatomaceous Earth?

Like I touched on in the into, diatomaceous earth is a type of natural powder that comes from sedimentary rock. This rock is siliceous, which means its main constituent is silica. Sometimes, diatomaceous earth is referred to as kieselguhr or diatomite, but it’s still the same thing.

The rock in diatomaceous earth gets broken down into a powder with a distinct white hue. Like most particles, the powder has various micron sizes, with the smallest pieces about a millimeter (three microns) and the biggest ones up to 200 microns. The porous qualities of diatomaceous earth make it highly sought-after for indoor and outdoor gardeners. It’s also not very dense.

What’s in diatomaceous earth, anyway? That’s a good question! It mostly consists of silica, with 80 to 90 percent of diatomaceous earth made from salt. That’s because the sedimentary rock that diatomaceous earth is sourced from is siliceous, as we said. Iron oxide (0.5 to two percent), and alumina (two to four percent) also comprise diatomaceous earth. The latter is in there because this powder also contains clay minerals.

The reason diatomaceous earth is called that is due to the presence of diatoms in fossilized form. Diatoms are an algae group that includes shells when used in diatomaceous earth. This earth also appears in products like dynamite (as a stabilizer), cat litter, plastic film anti-block, rubber and plastic reinforcing filler, coating matting agents, mechanical insecticides, toothpaste, and metal polish.

If you’ve ever handled pumice powder before, then you’ll have a pretty good idea of what diatomaceous earth feels like. It’s semi-abrasive and not as soft as it looks.

How Does Diatomaceous Earth Benefit Your Indoor Garden?

Okay, so you have a pretty good understanding of what diatomaceous earth is, but where does it fit in your indoor garden? I’m glad you asked! As I mentioned before, diatomaceous earth is mostly used for indoor pest control, but it has even more purposes than that.

Let’s discuss these now.


As a Plant Medium for Greater Porosity

You may remember from reading some of our previous articles that some houseplants need potting soil while others are more suited for potting mix. The latter sometimes uses a medium or several media with a different texture than the soil (if the houseplant requires soil at all). Well, diatomaceous earth happens to be a pretty good medium. It can’t give your houseplants much nutrition by itself though, so you should combine the diatomaceous earth with other media for best results.

If you have Bonsai plants or other indoor plants you’re growing in hydroponic containers, then you don’t want to skip the diatomaceous earth. It will serve your houseplants best when you combine it with potting soil. Not only does the root zone get more air, but the porosity of diatomaceous earth enhances drainage as well.

For Deodorizing Your Houseplants

Have you ever noticed that sometimes your houseplants get a little stinky? It happens. Even normally fragrant plants can go sour, often because of excess watering. The odor you’re smelling could be the development of mildew, mold, or funguses.

In other cases, you could add compost to your indoor plants, but man, does it reek. To combat the smell, try applying some diatomaceous earth. It’s a natural deodorizer that will erase unpleasant odors so you don’t have to move your precious houseplants outside.

While I’m on the subject of bad smelling indoor plants, I feel it only fair to mention that we actually have an article on , indoor plants that can make your house smell better, so you might want to read that article when you have time.

Pest Control

One of the areas where diatomaceous earth undoubtedly excels the most is pest control. Lots of insects will stay away once you sprinkle a little diatomaceous earth on the topsoil of your houseplants.

The first of these? Mites and ticks. You might keep your houseplants indoors now, but that might not have always been the case. Tiny insects like mites and ticks could have jumped onboard one or more of your houseplants while they were left outside. If you have any pets in your home, developing conditions like Lyme disease and Colorado tick fever is higher when your bringing in plants from outside that could now contain mites or ticks.

Along with pets, people can get these conditions, too. By using an indoor-friendly form of pest control, such as diatomaceous earth to eliminate these potential hazards , you can greatly reduce the chances of having mites and ticks that have hitched a ride on your houseplants in your home.

Besides mites and ticks, ants also dislike diatomaceous earth. That’s a good thing, because they can transport insects like aphids to your indoor plant, giving them a new place to live. Speaking of aphids, they like to invade your young plants, drinking all the sap they can get. Your poor houseplant then never grows to full capacity.

If you have other houseplants, aphids will move on to them too, potentially creating viruses in their wake. While chemical-laden products like pesticides will kill aphids on the spot, diatomaceous earth can also get rid of them without damaging your houseplant. You don’t have any dangerous fumes to breathe in while at your home or office either.

I’m not done yet!

Flies are another insect that will go elsewhere if you spread diatomaceous earth. Specifically, black flies, also known as fungus gnats, hate this powder. While I recommend sprinkling the diatomaceous earth on your houseplants top soil as well as around the pot if possible. Just so you know, should you cover a black fly with some diatomaceous earth, they become dehydrated and die.

While slugs can’t get into your home or office super easily, it’s not impossible, either. If you ever spot one, you don’t need salt. Diatomaceous earth will keep slugs from proceeding to your plant if you pour some in a ring around the threatened houseplant. The diatomaceous earth can actually cut the snail’s delicate skin, making it turn tail and leave.

Keeping Your Manure and Compost Maggot-Free

When it comes to making natural fertilizer, manure is a great ingredient (yes, even though it’s gross). Many gardeners, myself included, will also use compost for their houseplants. If you rely on either of these products even semi-regularly, there’s always the possibility that maggots can invade your houseplants. These gross bugs like unfinished compost and manure especially.

You might not even notice the maggot larvae wriggling in your manure or compost until it’s too late. You obviously can’t use this on your houseplants, so now it’s back to square one. Like many other insects, diatomaceous earth powder can keep maggots away without you having to shop for strong, damaging chemicals.

How to Use Diatomaceous Earth

The above applications prove how useful diatomaceous earth is to indoor gardeners. While we mentioned in the last section a few basic tips about where to put the powder, how exactly do you use diatomaceous earth?

You always want to make sure you wear a breathing mask and rubber gloves when handling diatomaceous earth. If it gets in your eyes or on your fingers and you then rub your eyes, they can turn red and sore. Diatomaceous earth can also affect your skin if it’s especially sensitive, causing redness and maybe even rashes.

We do want to reiterate that diatomaceous earth isn’t poisonous. It’s just not a good idea to get your face too close to it. That goes for just about all products you use to maintain your indoor garden.

With your safety supplies on, you just want to sprinkle the powder where you need it most. The bags of diatomaceous earth I buy, as seen in the image at the top of this post, actually comes with a small plastic scooper with measurements etched on the side of it for applying the diatomaceous earth. For applying larger amounts, consider sacrificing an old spoon or measuring cup. If you have a bit too much near your houseplant, you can dust off the excess diatomaceous earth with your fingertips, but otherwise, try to avoid direct handling.

Indoor gardeners have found out the hard way that diatomaceous earth with bigger particles can get stuck in a vacuum’s filter. If you have too much powder on the floor, maybe use a broom to sweep it up. Your vacuum will thank you.

Related Questions

Does diatomaceous earth kill plants?

When you were applying your diatomaceous earth, some of the powder got onto your plant, like more than you wanted. Do you have to worry about your plant dying?

Nope, not at all. Diatomaceous earth is a totally natural product. You can apply it on the soil’s surface and on your plant’s leaves. It can even get in the soil to increase porosity.

How often should you apply diatomaceous earth?

You’ve just started using diatomaceous earth for your indoor garden and you love it! Your houseplants have never been free of critters to this degree before. The question is, how often should you replace the diatomaceous earth?

It depends on the purposes you’re using it for. If it’s to ward off certain critters and insects, then it doesn’t hurt to always have some of the powder near your houseplant. Otherwise, apply when you know your trouble insect begins reappearing, often in the spring.

Can garden worms be killed with diatomaceous earth?

Most worms are quite harmless in a garden; in fact, earthworms can act as a natural tiller of soil to maintain its quality. Diatomaceous earth has no effect on earthworms and their fellow warm-blooded brethren.

Fred Zimmer

I'm a lover of plants, animals, photography, & people, not necessarily in that order. Currently, I'm focused on photographing indoor plants & chachkies. I write & rewrite articles about creating an environment where indoor plants can thrive. I'm good at listening to music but bad at shopping to muzak.

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