Meet Diatomaceous Earth: The Non-Toxic Pest Control For Home And Garden

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Diatomaceous earth is a naturally occurring substance used in a wide range of products, from plant-based foods and dietary supplements to cat litter and paint. It's even a stylish alternative to your boring dish-drying mat, quickly soaking up and evaporating water to prevent the buildup of bacteria and mildew. However, it's more well-known as a non-toxic method of pest control that you can use in your garden and other places around your home where pests are problematic.

Made from fossilized diatoms — small aquatic organisms — that accumulate in lake, river, ocean, and stream sediment over time, diatomaceous earth was first used in pesticide products in 1960. It has been extensively used to deter and kill ants, bed bugs, beetles, cockroaches, earwigs, fleas, silverfish, slugs, spiders, and ticks, but it is likely effective against almost any insect. While you may have heard of repurposing eggshells in your garden to deter caterpillars, slugs, and snails, diatomaceous earth works against more pests and does more than just prevent them.

That's because diatom skeletons are mostly made of silica, which absorbs the oils and fats from insects, causing them to dry out. It takes anywhere from a few hours to a few days for this pest control method to work, depending on the insect. Best of all, it's not toxic to animals or humans when you choose the food-grade variety.

There are a couple of ways to use diatomaceous earth around your home and garden, depending on where you use it and the type of product you choose. If you're starting your own kitchen herb garden or have a larger garden that you want to protect against damaging bugs, spread a thin layer of diatomaceous earth on top of the soil around your plants. You can spread Harris food-grade diatomaceous earth using a kitchen sieve or sifter, just as you would for baking. Since pests will evade walking through thick layers, these tools ensure that you get a fine layer that they cannot avoid.

If you have planters, though, you could use Harris food-grade diatomaceous earth in a puffer-tip bottle to apply a thicker layer around the bases of the planters to deter pests from crawling up into them from the start. This type of applicator is useful for placing diatomaceous earth in deck and patio cracks and crevices, as well as around baseboards, beds, carpets, door frames, furniture, windowsills, and more, outside and inside your home, where you see unwanted pests. You can even use it directly on insects as they appear and watch it work in real-time.

Before you grab a bag or bottle of diatomaceous earth to spread around your home and garden, there are a couple of safety precautions to take. This product is natural and safer than an insecticide, but it's also dusty and can cause irritation if inhaled or gets into your eyes. Because of this, it's recommended that you wear a mask over your nose and mouth, as well as a pair of safety goggles (or something similar), to prevent dust from getting into your nasal passages, lungs, and eyes.

You'll want to avoid direct contact (yours and your pets, if you have any) because diatomaceous earth is absorbent and can dry out your skin, too. Wearing long sleeves, pants, and gloves and keeping pets at a distance during the application can help protect everyone's skin. For the same reason, you should make sure that indoor spaces are well-ventilated. And, if you're using it to control pests around edible plants, apply it well before it's time to harvest the food, and always wash them thoroughly before eating.

Also, you can follow a few tips to improve the effectiveness of diatomaceous earth. For instance, pests are most active in the evenings, so wait until later in the day to spread the powder. Keep in mind that this product is less effective for pest control when it's wet, so you will likely need to reapply it after heavy watering, rain, or a substantial morning dew. Don't be afraid to dust the tops and undersides of your plants' leaves either, which will help get rid of spider mites. Most importantly, refer to the label on your specific diatomaceous earth for complete instructions on its use.