Lawns may be re-seeded when crabgrass is dead. You may also fertilize the entire lawn with a product such as GreenSweep Lawn Food to promote growth of desirable grasses to fill in the bare spots. Visible signs of death, yellowing and spotting of top growth, should occur on most weeds within 4 to 7 days after the last application. The treated weeds then wither, turn brown and die. The appearance is similar to grass that has been frosted.
Higher temperatures result in quicker uptake of the product for faster control.
Two applications 4 to 7 days apart are needed for control of medium to mature crabgrass. Higher temperatures result in a quicker uptake of this product for faster control. Do not apply Crabgrass Killer if temperatures exceed 90 degrees. If daytime temperatures are expected to exceed 90 degrees, apply the product in early morning when temperatures are cooler. Late afternoon application may be diluted or washed off leaves by dew or rainfall during the night resulting in unsatisfactory control of weeds.