How to Spread Diatomaceous Earth on Lawn? A Definitive Guide

Spreading diatomaceous earth (DE) on your lawn involves more than just sprinkling it around; proper application is key to effectively controlling pests. This guide provides a comprehensive overview of how to correctly apply DE to your lawn for optimal results, focusing on timing, technique, and safety precautions.

Understanding Diatomaceous Earth and Its Benefits

Diatomaceous earth is a naturally occurring, sedimentary rock composed of the fossilized remains of diatoms, a type of hard-shelled algae. It’s a powerful, yet safe, organic insecticide when used correctly. The sharp, microscopic edges of the diatoms abrade the waxy exoskeletons of insects, causing them to dehydrate and die.

Food Grade vs. Filter Grade: Choosing the Right DE

It’s crucial to understand that there are two main types of diatomaceous earth: food grade and filter grade. Filter grade, often used in swimming pool filters, is treated and not safe for use in gardens or around pets. Always use food grade diatomaceous earth on your lawn and garden. This type is safe for humans, pets, and beneficial insects when applied correctly.

Pests Controlled by DE

Diatomaceous earth is effective against a wide range of lawn pests, including:

• Ants
• Fleas
• Ticks
• Slugs and Snails
• Earwigs
• Cutworms
• Chinch bugs

The Art of Application: How to Spread DE Effectively

The effectiveness of diatomaceous earth hinges on proper application. Simply scattering it haphazardly won’t yield the desired results. Here’s a step-by-step guide to spreading DE effectively on your lawn:

1. Choose the Right Day: Ideally, apply DE on a dry, windless day. Rain will wash it away, and wind will scatter it, reducing its effectiveness.
2. Prepare Your Lawn: Mow your lawn before applying DE. This allows the DE to reach the soil surface and target pests that live there. Rake away any excessive thatch.
3. Use a Duster or Spreader: A garden duster or a seed spreader (for larger areas) provides the most even coverage. Avoid using your hands, as the dust can be irritating.
4. Apply a Thin, Even Layer: The goal is to coat the grass blades and soil surface with a thin, even layer of DE. Avoid piling it up. A thick layer is no more effective and can smother the grass.
5. Focus on Problem Areas: Pay particular attention to areas where you’ve noticed pest activity, such as ant mounds or patches of dead grass.
6. Reapply After Rain or Watering: DE is only effective when dry. Reapply after rain or watering to maintain its insecticidal properties.

Specific Application Tips for Different Pests

• Ants: Apply DE directly to ant mounds and around the perimeter of your house.
• Fleas and Ticks: Focus on areas where pets frequent, such as dog houses, shady spots, and under decks.
• Slugs and Snails: Create a barrier around vulnerable plants, such as vegetables and flowers.

Safety Precautions When Using Diatomaceous Earth

While food grade DE is considered safe, it’s still important to take precautions:

• Wear a Dust Mask: DE can irritate the lungs if inhaled. A dust mask will protect you from breathing in the fine particles.
• Wear Gloves: Prolonged contact with DE can dry out your skin. Gloves will help prevent irritation.
• Avoid Eye Contact: If DE gets in your eyes, flush them thoroughly with water.
• Keep Out of Reach of Children and Pets: While food grade DE is safe if ingested in small quantities, it’s best to keep it out of reach of children and pets to prevent accidental inhalation or ingestion.

FAQs About Using Diatomaceous Earth on Lawns

Here are answers to some frequently asked questions about using diatomaceous earth on lawns:

FAQ 1: How long does it take for diatomaceous earth to kill pests?

It typically takes a few hours to a few days for diatomaceous earth to kill pests. The exact timeframe depends on the type of pest, the size of the infestation, and the effectiveness of the application.

FAQ 2: Can I use diatomaceous earth indoors to control pests?

Yes, you can use food grade diatomaceous earth indoors to control pests like ants, cockroaches, and bed bugs. Apply a thin layer in areas where you’ve seen pest activity, such as along baseboards, under appliances, and in cracks and crevices.

FAQ 3: Will diatomaceous earth harm my grass?

No, food grade diatomaceous earth will not harm your grass when applied correctly. In fact, some believe that the trace minerals in DE can even benefit the soil.

FAQ 4: Is diatomaceous earth safe for beneficial insects like bees?

Diatomaceous earth can harm beneficial insects if they come into direct contact with it. To minimize the risk, avoid applying DE to flowers or areas where bees are actively foraging. Apply it in the early morning or late evening when bees are less active.

FAQ 5: How often should I reapply diatomaceous earth to my lawn?

Reapply diatomaceous earth after rain or watering, as it is only effective when dry. You may also need to reapply it periodically, especially during periods of heavy pest activity.

FAQ 6: Can I mix diatomaceous earth with water and spray it on my lawn?

While you can mix DE with water, it’s not the most effective method. When wet, DE loses its abrasive properties, which are essential for killing insects. It’s best to apply DE dry.

FAQ 7: Does diatomaceous earth expire?

Diatomaceous earth does not expire as long as it’s stored in a dry place. However, it’s best to use it within a few years of purchase to ensure its effectiveness.

FAQ 8: Can I use diatomaceous earth on my vegetable garden?

Yes, food grade diatomaceous earth is safe to use on your vegetable garden to control pests. Apply it directly to the plants, avoiding the flowers to protect pollinators.

FAQ 9: Will diatomaceous earth kill earthworms?

Diatomaceous earth can potentially harm earthworms if they come into direct contact with it. However, earthworms typically live deep within the soil, so the risk is relatively low. Avoid applying DE heavily to areas where earthworms are abundant.

FAQ 10: What is the best way to store diatomaceous earth?

Store diatomaceous earth in a dry, airtight container in a cool, dark place. This will prevent it from clumping and losing its effectiveness.

FAQ 11: Can I use diatomaceous earth to control fleas on my pets?

Yes, you can use food grade diatomaceous earth to control fleas on your pets. Gently rub a small amount into their fur, being careful to avoid their eyes and nose. Vacuum thoroughly afterwards. Consult with your veterinarian before using DE on your pet, especially if they have any underlying health conditions.

FAQ 12: Where can I buy food grade diatomaceous earth?

Food grade diatomaceous earth is readily available at garden centers, hardware stores, and online retailers. Make sure to check the label to confirm that it is food grade and safe for use around humans and pets.

By following these guidelines, you can effectively and safely use diatomaceous earth to control pests in your lawn and garden, creating a healthier and more enjoyable outdoor space. Remember, consistent and careful application is key to success.