Harris food-grade diatomaceous earth (DE) is composed of 100% ground freshwater DE, with no additives. The product is made of the naturally occurring fossilized remains of diatoms, a type of algae that forms in freshwater. These remains are ground up into a soft, fine white powder that carry many different uses. It's chemical-free and completely safe to use around children and pets. Harris diatomaceous earth is listed with the organic minerals research institute (OMRI) for organic use. It's mined in Nevada and packaged in Georgia in airtight bags. Included in the bag is a powder duster, allowing for easy application of a fine dusting of powder.
How diatomaceous earth works
If you looked at food grade, uncalcined diatomaceous earth on a microscopic level, it would look like a multitude of tiny hollow cylinders covered in barbs. These barbs make a very effective deterrent against a broad spectrum of insects.
As an insect or bug treads across the powder, the tiny barbed cylinders penetrate the waxy coating that covers the insect’s body. This creates wounds that let body fluid out. The porous nature of the powder also makes it absorbent. This means diatomaceous earth works in two ways, both injuring the pest and drawing out fluid to dry and kill the insect. Death does not happen on contact, but over a short period of time. If left undisturbed, diatomaceous earth can be effective within 24 hours, though better results are usually apparent after five days.
Several factors will influence the success of diatomaceous earth: the type of insect, size of infestation, temperature, and humidity. Because diatomaceous earth is so absorbent, excessive moisture or rain can limit its effectiveness. DE will be less effective if applied too thinly; better to lay out ‘lines’ of DE rather than dusting an area.
Additionally, all insects are susceptible to DE, even the good ones. In gardening, this means it’s essential to limit your application to wherever the pests exist and not where beneficial insects dwell. Don’t apply to flowers or known ground beetle habitat.
If applied correctly, diatomaceous earth is:
-Non toxic to pets or humans
-A versatile pest management tool
Diatomaceous earth for controlling insect pests in the garden
Garden pests are controlled most successfully with DE when the product can be kept dry and out of the way of beneficial insects.
For bulbs: Just prior to planting, dip and coat entire bulb or existing stem in DE to address any dormant bulb thrips, borer, or mites.
In the greenhouse: Sprinkle a perimeter barrier of DE around seeding trays for pill bugs and around the base of small plants to protect against earwigs.
In the garden: When plant leaves are dry with a forecast of good weather, dust plants with diatomaceous earth to help control asparagus beetle, Mexican bean beetle, potato beetle and cutworm.
For aphids: Dust under the leaves and directly into infestations of aphids on cabbages, broccoli, kale, and cauliflower.
Avoid putting DE directly on flower heads because bees are especially susceptible to the effects of the dust.
Use Caution: DE is harmful if inhaled. Keep out of reach of children and pets. Always read product labels before using.
** The 50 lb bag is from a different supplier. It is still food grade but it comes in paper food grade packaging and does not include a duster.