What Is Diatomaceous Earth?
What Is Diatomaceous Earth?
Diatomaceous earth (DE), also known as diatomite, is a naturally occurring, soft sedimentary rock that can be ground into a fine, off-white powder. It’s composed predominantly of silica—about 80–90%, with smaller amounts of alumina (2–4%) and iron oxide (0.5–2%) (Amazon, Wikipedia). DE originates from the fossilized remains of diatoms, which are single-celled aquatic algae (Wikipedia).
Looking to try DE for yourself? Get yours now on Amazon — a small commission may be earned by me, at no extra cost to you.
-
Food‑grade DE: Low in crystalline silica (<1%), deemed safe for gardens, livestock feed, and household use (Amazon.
-
Filter (pool)‑grade DE: Heat-treated (calcined) to enhance filtration, often with high crystalline silica content (upwards of 60%), and not safe for pest control or ingestion (Wikipedia).
DE functions as a mechanical insecticide. Its microscopic, sharp particles damage the outer waxy layer of pests—be it exoskeletons or slimy skin—leading to dehydration and eventual death.
Because it acts physically rather than chemically, pests cannot develop resistance to DE over time. It performs best in dry, undisturbed environments—its effectiveness drops rapidly when wet and it often needs reapplication after rain or watering.
What Pests Can DE Target?
DE can be effective against a wide range of crawling pests:
Insects & Arthropods
Commonly affected pests include:
-
Ants, fleas, bed bugs, cockroaches, spiders, ticks, mites, and crickets.
-
Beetles such as Japanese beetles, flour beetles, millipedes, cutworms, centipedes, aphids, and more .
-
Many indoor and outdoor crawling insects in general (Amazon).
Manufacturer labels—like that of Bonide—often list a broad spectrum, including ants, cockroaches, slugs, millipedes, fleas, bedbugs, beetles, grasshoppers, centipedes, and more (Amazon).
Slugs & Snails
DE can act as a deterrent for slugs and snails, creating a rough or drying barrier that may discourage them from crossing.
However:
-
Its lethality against slugs and snails is inconsistent and debated, especially since these mollusks prefer moist environments, which also neutralize DE’s abrasive effects.
-
Some reports indicate slugs and snails simply avoid the DE, rather than being harmed by it (Empress of Dirt).
-
Reddit discussions echo this uncertainty—DE may cause discomfort or slow them down, but it probably won’t kill them outright (Reddit).
Bottom line: DE is better as a physical barrier against slugs and snails, but shouldn't be relied upon as a primary killer.
Safety & Environmental Considerations
For Humans & Pets
-
Food‑grade DE is generally regarded as safe and even used as an anti-caking agent in feed or clarifier in food processing (National Pesticide Information Center).
-
The main hazard comes from inhalation of dust, especially crystalline silica, which can cause lung irritation, respiratory issues, and in extreme cases (especially with filter-grade DE) may contribute to silicosis (Wikipedia).
-
To minimize risk:
-
Always use food‑grade DE for household or gardening applications .
-
Avoid breathing the dust—wear a mask, gloves, and goggles during application.
-
Keep children and pets away until the dust settles (The Spruce Pets).
-
Environmental Impact
-
DE is eco-friendly and natural, does not break down into harmful residues, and is unlikely to negatively impact soil or water systems.
-
It may harm beneficial insects, including pollinators like bees, ladybugs, and lacewings, due to its broad-spectrum action.
-
Because DE remains where applied until washed away, it poses low long-term environmental risk (National Pesticide Information Center).
Summary Table
| Aspect | Details |
|---|---|
| Origin | Fossilized diatoms—microscopic algae (mainly silica) |
| Effective Against | Insects with exoskeletons (ants, fleas, bed bugs, beetles, etc.) |
| Slugs & Snails | Barrier/deterrent; inconsistent lethality |
| Effectiveness | Physical desiccation; works only when dry |
| Use Tips | Apply in thin layers; reapply after rain; avoid excessive use |
| Safety | Food-grade is safe if used cautiously; inhalation risk—use PPE |
| Environmental Impact | Non-toxic, but can harm beneficial insects; eco-friendly overall |
Final Thoughts
Diatomaceous earth is a valuable organic, non-chemical pest control tool—especially effective against hard-bodied insects such as ants, cockroaches, fleas, and beetles. It's also handy as a mechanical barrier for soft-bodied pests like slugs and snails, though its lethality is limited and application context matters (dry vs. moist environments).
The key to safe and effective use:
-
Choose food-grade DE.
-
Apply it sparingly and strategically, maintaining dryness.
-
Protect yourself and non-target creatures (like pollinators) during application.
-
Use DE as part of a holistic pest control strategy, not a standalone solution.
