Understanding Ground Freshwater Diatomaceous Earth
Diatomaceous earth (DE) is a mineral powder derived from the fossilized skeletons of single-celled algae known as diatoms. These fossilized shells, composed of amorphous silica, are mined from ancient lake beds. Under a microscope, the particles appear like tiny, sharp cylinders or honeycombs. It is this unique, abrasive structure that is key to its functionality as a mechanical insecticide. Unlike chemical pesticides, insects cannot develop a resistance to DE because it kills them through a physical process rather than a chemical one.
To be safe for use around humans and pets, it is critical to use food-grade diatomaceous earth, which is derived from freshwater sources and contains less than 1% crystalline silica. The other primary type, filter-grade DE, is heat-treated and not safe for ingestion or broad household use due to its higher crystalline silica content.
Primary Uses for Ground Freshwater Diatomaceous Earth
This all-natural powder boasts a surprising number of applications. Its mechanical and absorbent properties make it a safe and effective alternative for many household and garden needs.
Natural Pest Control in the Home and Garden
One of the most popular uses for ground freshwater diatomaceous earth is as a non-toxic insecticide for crawling pests. When an insect with an exoskeleton comes into contact with the fine powder, the microscopic edges scratch their waxy protective coating. This causes the insect to lose moisture and dehydrate, leading to death. It is effective against a wide array of pests, including:
- Ants
- Cockroaches
- Bedbugs
- Fleas
- Mites and spider mites
- Earwigs
- Crickets and silverfish
- Slugs and snails
For pest control, DE must be applied in a dry state. To treat indoor infestations, apply a light dusting in cracks, crevices, behind appliances, and along baseboards where pests travel. For gardens, create a protective barrier by sprinkling it in a continuous line around vulnerable plants.
Uses for Pet Care
Food-grade DE is a common natural remedy for pet owners combating parasites.
- Internal Parasite Control: When mixed with a pet's food, DE can act as a dewormer, helping to eliminate internal parasites. This must be done carefully, following a veterinarian's guidance, and over a period of 30 consecutive days to catch the parasites' full life cycle.
- External Pest Control: For fleas and ticks, DE can be lightly rubbed into a pet's coat, avoiding their eyes and nose. It can also be dusted on pet bedding and carpet, and then vacuumed up after a few days to remove dead pests and eggs.
Household and General Applications
DE's high absorbency makes it useful beyond pest control.
- Deodorizing: Sprinkle DE at the bottom of trash cans, in refrigerators, or in smelly areas like cat litter boxes to neutralize odors.
- Cleaning: Its mildly abrasive texture makes it an effective and non-toxic scouring agent for tough stains on sinks or driveways.
- Dry Food Storage: When added to stored grains, flour, or legumes, DE helps prevent caking and protects against insect infestations by keeping the contents dry.
Garden and Soil Improvement
In addition to pest control, DE can be a beneficial soil additive.
- Soil Amendment: Mixing DE into clay-heavy soil improves drainage and aeration, which is especially beneficial for potted plants and bonsai trees.
- Water Retention: Its porous structure helps soil retain water and nutrients, releasing them slowly to plant roots.
- Seed Treatment: Coating seeds with a thin layer of DE before planting can protect them from certain pests.
Comparison of Diatomaceous Earth Grades
It is crucial to use the correct grade of DE for your intended purpose. The table below outlines the key differences between food-grade (freshwater) and filter-grade (saltwater) DE.
| Feature | Food-Grade (Freshwater) | Filter-Grade (Saltwater) |
|---|---|---|
| Source | Mined from freshwater lake beds | Mined from marine deposits |
| Processing | Minimally processed and uncalcinated | Heat-treated (calcined) |
| Crystalline Silica Content | Very low, typically less than 1% | Very high, can exceed 60% |
| Safety Profile | Non-toxic to humans and pets (when handled properly) | Harmful if inhaled or ingested |
| Primary Uses | Insect control, dietary supplement (with caution), household cleaning | Swimming pool filters, industrial applications |
| Particle Size | Very fine powder | Larger, coarser particles |
Important Safety Precautions
While food-grade DE is safe for many applications, proper handling is essential. The fine dust can be irritating to the lungs, eyes, and nasal passages if inhaled. Always wear a dust mask, gloves, and goggles when applying, especially in confined spaces. Apply on calm days to prevent the dust from becoming airborne. For indoor use, ensure good ventilation and only apply a thin layer. Keep children and pets away from the area during and immediately after application.
Conclusion
Ground freshwater diatomaceous earth is an incredibly versatile, natural, and low-cost product with a wide range of uses in the home, garden, and for pet care. By understanding how its unique physical properties—microscopic sharpness and high absorbency—function, you can effectively use it as a non-toxic mechanical insecticide, a deodorizer, and a soil amendment. Always ensure you purchase food-grade DE and follow safety precautions to protect yourself and your family from respiratory irritation. Its ability to combat pests and absorb odors without harsh chemicals makes it an essential tool for those seeking a more natural and sustainable lifestyle.
For more information on safe pesticide usage, consult the National Pesticide Information Center at npic.orst.edu.
