Our yard was hopping with fleas when we moved in years ago. It was so gross. The first spring I sprayed nematodes all around the yard. They are microscopic predators to fleas. It made a huge difference. The nematodes are sold at at garden centers, they need to be refrigerated until used, they are sold on a small piece of foam that can be squeezed into a clean one gallon garden sprayer. I wait for a rainy day in June when the soil temps were warm enough for the nematodes to be active and the rain can soak them into the soil. Sprayed them on the grass once a year for a couple of years then every other year. Nice not to have to use chemicals on the yard if possible. Depending where you live nematodes might not be the answer.
