How to Kill Post-Emergent Crabgrass


Crabgrass is a weed grass that spreads out in a dense, low-growing mat that produces long, three-pronged seed heads. Crabgrass overwinters in lawns as seed and springs up in the hottest parts of summer when the lawn is weakened by lack of water. It thrives in full, hot sun and will be killed by the first frost of the year. The best defense against crabgrass is to mow your grass high so that the seeds cannot get the light they need to germinate. However, once crabgrass emerges, you must resort to other means of removal.

Step 1

Spread a drop cloth around the crabgrass to protect beneficial grass from the herbicide's overspray.

Step 2

Spray a broad-spectrum herbicide directly on the crabgrass. Allow the crabgrass to turn brown and die. Remove the grass and its roots from your lawn with a trowel.

Step 3

Remove older crabgrass by digging it out of the soil with a garden trowel. Crabgrass will not return if you pull all of its roots up.

Things You'll Need

  • Broad-spectrum herbicide
  • Drop cloth
  • Garden trowel


  • Iowa State University: Acetic Acid (Vinegar) for Weed Control Revisited
  • University of Minnesota Extension: Controlling Crabgrass
  • University of Minnesota Extension: Crabgrass Control

Who Can Help

  • NC State University Extenson: Weed Management in Annual Color Beds
Keywords: killing crabgrass, broad spectrum herbicide, eliminating weeds

About this Author

Tracy S. Morris has been a freelance writer since 2000. She has published two novels and numerous online articles. Her work has appeared in national magazines and newspapers, including "Ferrets," "CatFancy," "Lexington Herald Leader" and "The Tulsa World."