A flea infestation can be a major problem that can keep you from enjoying your garden. But although fleas can be virulent, there is no need to coat your yard with noxious chemicals. There are several ways to kill fleas in your yard organically and effectively without making your garden a toxic place to work.
Apply diatomaceous earth to your yard according to the manufacturer's instructions. Diatomaceous earth is made of the crushed, fossilized bodies of aquatic animals. When applied in the yard, the sharp edges of diatomaceous earth slice through the bodies of adult fleas, larvae and eggs to kill them. Pay special attention to your garden or flower bed, around trees or other yard structures, the perimeter of your lawn and any place that your pet frequents. Retreat your yard and garden every two months.
Apply an organic yard spray that features pyrethrum as its active ingredient. Pyrethrum is an organic flea killer that is extracted from chrysanthemum flowers. Pyrethrum is available as a room fogger and home spray as wells as a yard spray. For pyrethrum to be optimally effective, you should apply it indoors as well as out according to the manufacturer's instructions.
Purchase nematodes. Nematodes are microscopic worms that feed voraciously on fleas (and other harmful insects) and have reported to end an infestation in as little as 48 hours. They can be purchased online or from your local garden center, added to water and sprayed over your yard or garden according to the manufacturer's instructions.