How to Kill Crabgrass


Crabgrass grows during summer months and is a particularly unwanted weed for many gardeners. The best way to avoid weeds like crabgrass is to constantly practice lawn maintenance and use the right chemicals. Crabgrass is light green with thick stems that form a circle near the ground. The grass will quickly spread throughout your yard and around your garden as soon as you notice that it has developed. It's best to take care of the crabgrass immediately to prevent more crabgrass from appearing.

Step 1

Start to control the crabgrass by using a pre-emergent herbicide. Use the herbicide in spring before any seedlings appear in your yard. Make sure that the pre-emergent herbicide you purchase contains oxadiazon, pendimethalin, siduron, benefin and bensulide.

Step 2

Use postemergent herbicide if the crabgrass still grows in early summer. Spray at least 1 inch away from the seedling and in any other areas where the crabgrass could grow.

Step 3

Have a company like TruGreen help you with killing the crabgrass if you can't kill it yourself with the postemergent herbicide.

Step 4

Reduce the need to constantly kill crabgrass by maintaining your lawn properly. Different types of grass have different optimal heights of growth; let your grass grow to the longer side of this range in order to provide more shade and coolness for your soil, which helps prevent weed growth.

Step 5

Fertilize your grass in early spring and late fall so that you don't help the weeds grow. Never fertilize during hot periods in the summer, and don't water areas where the crabgrass is growing; weeds need moisture to flourish.

Tips and Warnings

  • Always read the label for the crabgrass killer as some chemicals hurt certain varieties of lawn. For example, centipede grass and St. Augustine can die from crabgrass killer. Also, don't mow prior to spraying and don't water the area for 24 hours after spraying.

Things You'll Need

  • Pre-emergent herbicide
  • Postemergent herbicide


Keywords: get rid of weeds, kill crabgrass, maintaining grass

About this Author

Greg Lindberg is a graduate of Purdue University with a Bachelor of Liberal Arts degree in creative writing. His professional writing experience includes three years of technical writing for an agriculture IT department and a major pharmaceutical company, as well as four years as staff writer for a music and film webzine.