Things You'll Need
Water hose or sprinklers
Having fleas around your yard not only provides an inconvenience, with itchy bites and annoying infestations, but also poses a health risk. Fleas potentially carry a wide array of diseases, including heavy-hitters like plague. To combat this, many homeowners turn to borax. Borax affects fleas in a similar way to its affect on roaches -- it poisons them after the bugs ingest it. While flea control outdoors may be rather hard, borax can be beneficial to curb an infestation and keep your family and pets safe.
Apply the borax when there will be no precipitation for at least 72 hours. Applying borax to your lawn before a big rain could cause the borax to wash away before it really has an effect on the flea population in your lawn.
Observe high flea population areas. These tend to be areas in which animals frequent, such as doghouses or food areas.
Apply the borax lightly within the areas that you suspect fleas populate, or cover the whole lawn for total protection. Try not to be too heavy-handed with the borax sprinkling, as a large amount of borax can kill plants. If applying pure borax to your lawn troubles you, mix the borax with natural diatomaceous earth. Diatomaceous earth acts as another flea control product, dehydrating fleas to kill them.
Keep your family and any pets away from the yard as the borax or borax/diatomaceous earth mixture sets in for the next three days. While diatomaceous earth is nontoxic, borax can be a toxin if it gets into broken skin or if ingested. The U.S. Forest Service notes that borax can cause nausea and vomiting, and in children shock and death can occur upon ingestion.
Wash away the borax after three to four days. By this time, the fleas in your lawn should have ingested the borax or absorbed the diatomaceous earth. Allow the lawn to dry completely before allowing your family and pets outside to play again.
You may have to repeat this process a few times to ensure the fleas and all the eggs are killed. Try performing this in spring, when the flea population is likely at a boom. If the infestation has moved indoors already, borax can be sprinkled onto your carpets to kill fleas.