The most effective way to kill crabgrass is to eliminate it in the spring with a pre-emergent herbicide. You then need to wait until late summer or early fall to reseed the area.Continue Reading
In the spring, after you have mowed your lawn at least twice, is the best time to apply a pre-emergent herbicide. Apply the herbicide before the crabgrass has sprouted. This product is granular and sits on your lawn. As the crabgrass begins to grow, it takes in the herbicide and dies. Combining the herbicide with a lawn fertilizer allows you to kill the crabgrass while feeding the rest of your lawn. Apply the mixture just before it is expected to rain, so the product soaks into the soil for better effect.
As a pre-emergent herbicide kills off new growth, you need to wait until the product is no longer active before you reseed the area where the crabgrass once was. In the late summer or early fall, once the crabgrass is eliminated, you may reseed any areas in need. Use a broadcast spreader for an even distribution of the seeds, and water the soil immediately after. Keep the area moist to promote quick germination of the grass seed.Learn more about Landscaping