How to Put Diatomaceous Earth on Plants? A Comprehensive Guide
Applying diatomaceous earth (DE) to plants is a simple, yet effective, method for pest control and even some nutritional benefits. The best way to apply DE is to dust it lightly and evenly onto the affected areas of the plant, ensuring full coverage, or mixing it into the topsoil around the base of the plant.
Understanding Diatomaceous Earth and Its Benefits
Diatomaceous earth is a naturally occurring, soft, sedimentary rock that is easily crumbled into a fine white to off-white powder. This powder is composed of the fossilized remains of diatoms, a type of hard-shelled algae. There are two main types of DE: food grade and filter grade. For use on plants, food grade DE is essential, as filter grade DE has been chemically treated and is unsafe for consumption and plant life.
DE works as an organic insecticide through its abrasive nature. The microscopic, sharp edges of the diatom skeletons damage the exoskeletons of insects, causing them to dehydrate and die. Additionally, DE contains silica, which can strengthen plant cell walls and improve resistance to certain diseases.
Applying Diatomaceous Earth: A Step-by-Step Guide
Here’s a breakdown of how to effectively apply DE to your plants:
1. Identify the Pest Problem
Before applying DE, accurately identify the pest causing the problem. DE is most effective against soft-bodied insects such as aphids, spider mites, slugs, snails, and flea beetles. It has limited effectiveness against insects with hard exoskeletons or those that don’t come into direct contact with the powder.
2. Choose the Right Type of Diatomaceous Earth
As mentioned earlier, always use food grade diatomaceous earth for plants. This type is safe for both plants and humans. Check the label to ensure it’s specifically designated as food grade.
3. Timing is Key
The best time to apply DE is during dry conditions. Wet DE clumps together and loses its abrasive properties. Apply it in the morning after the dew has dried or in the late afternoon to avoid direct sunlight.
4. Application Methods
There are two primary methods for applying DE to plants:
- Dusting: This involves lightly dusting the affected areas of the plant with DE. You can use a bulb duster, a flour sifter, or even a paintbrush to achieve even coverage. Pay particular attention to the undersides of leaves, where many pests like to hide.
- Soil Application: You can mix DE directly into the topsoil around the base of the plant. This helps control soil-dwelling pests and can also improve soil drainage. Gently work the DE into the top inch or two of soil.
5. Reapplication
DE loses its effectiveness when wet, so reapply it after rain or watering. Monitor your plants regularly and reapply DE as needed to maintain pest control.
6. Safety Precautions
While food grade DE is considered safe, it’s still essential to take precautions:
- Wear a dust mask: DE can irritate the lungs if inhaled.
- Avoid getting DE in your eyes: Wear safety glasses or goggles.
- Wash your hands after application.
FAQs About Using Diatomaceous Earth on Plants
Here are some frequently asked questions to further clarify the use of diatomaceous earth on plants:
FAQ 1: Can I use diatomaceous earth on edible plants?
Yes, you can absolutely use food grade diatomaceous earth on edible plants. It’s considered a safe and organic pest control method for fruits, vegetables, and herbs. Just be sure to wash your produce thoroughly before consuming it to remove any residual DE.
FAQ 2: How often should I apply diatomaceous earth to my plants?
The frequency of application depends on the severity of the pest infestation and the weather conditions. Generally, reapply after rain or heavy watering. In cases of severe infestation, you may need to apply it every few days until the pests are under control.
FAQ 3: Does diatomaceous earth harm beneficial insects?
Yes, DE can harm beneficial insects such as bees and ladybugs if they come into direct contact with it. Apply DE carefully and avoid dusting flowers or areas where beneficial insects are actively foraging. Consider applying it in the evening when pollinators are less active.
FAQ 4: Can diatomaceous earth be used to control slugs and snails?
Yes, DE is an effective barrier against slugs and snails. Create a ring of DE around vulnerable plants to prevent them from reaching the foliage. Remember to replenish the barrier after rain.
FAQ 5: Is diatomaceous earth effective against all types of plant pests?
No, DE is most effective against soft-bodied insects with exoskeletons that can be damaged by its abrasive properties. It’s less effective against pests with hard shells or those that don’t come into direct contact with the powder.
FAQ 6: Can I mix diatomaceous earth with water and spray it on my plants?
While you can mix DE with water to create a slurry, it’s generally less effective than applying it as a dry powder. The water will cause the DE particles to clump together, reducing their abrasive properties. If you choose to spray it, ensure the slurry is thin and reapply frequently.
FAQ 7: Can diatomaceous earth improve soil drainage?
Yes, adding DE to heavy clay soil can improve drainage and aeration. The porous nature of DE helps to break up compacted soil, allowing for better water and air circulation.
FAQ 8: What are the disadvantages of using diatomaceous earth on plants?
The main disadvantages are that DE is only effective when dry, it can harm beneficial insects, and it may require frequent reapplication. Additionally, inhaling DE can cause respiratory irritation.
FAQ 9: How long does diatomaceous earth last in the soil?
Diatomaceous earth can last for several months in the soil, but its effectiveness as a pest control agent will diminish as it becomes wet or covered with debris. Regular tilling and replenishment will help maintain its benefits.
FAQ 10: Can I use diatomaceous earth indoors on houseplants?
Yes, you can use food grade diatomaceous earth indoors on houseplants to control pests like aphids, spider mites, and fungus gnats. Follow the same application methods as you would outdoors.
FAQ 11: Where can I buy food grade diatomaceous earth?
Food grade diatomaceous earth can be purchased at most garden centers, hardware stores, and online retailers. Ensure the label clearly states that it is “food grade.”
FAQ 12: Does diatomaceous earth expire?
Technically, diatomaceous earth does not expire. However, it’s best to store it in a dry, airtight container to prevent moisture absorption. Over time, it may become less effective if it’s exposed to humidity.