How to Rid Your Lawn of Crabgrass

Overview

Crabgrass, a summer annual, has a tendency to make a gardener crabby. As soon as the soil begins to warm in the spring and on into fall, crabgrass can become abundant, spreading by seed and by rooting at the nodes. Keeping the lawn full and healthy is one way to prevent crabgrass from getting a foothold in the lawn. Once it's there, aside from hand-pulling, the best way to get rid of crabgrass is by using herbicide. Apply the herbicide prior to crabgrass seed germination, generally around mid-March (or when the soil begins to warm to over 50 degrees F), and again in mid-September.

Step 1

Pour the pre-emergent herbicide granules into the spreader. Crank the handle on the spreader as you walk the lawn, going north to south, in strips. Add more granules to the spreader and apply it as you walk east to west, over the entire lawn. This criss-cross-patterned application will help to ensure even coverage of the lawn.

Step 2

Water the area until the lawn is completely saturated after application. Water helps activate the herbicide.

Step 3

Re-apply the pre-emergent herbicide in September, or when the weather begins to cool, in the same manner that you applied it the first time.

Step 4

Spray post-emergent herbicide directly on young crabgrass that grows during the summer. Cover the entire plant with the spray, until it is wet and dripping.

Step 5

Prevent crabgrass by cutting your lawn as high as possible for the species of grass you are growing, but at least 2 inches. The longer grass height will create shade, which is the enemy of crabgrass. Watering less often, but deeper (to 4 to 6 inches deep) will keep crabgrass seeds from germinating.

Tips and Warnings

  • Read and follow all herbicide package directions and wear protective clothing during application. Do not use herbicides on newly planted sod. Experts with the University of California warn that if temperatures rise above 85 degrees F, reduce the rate of the herbicide to avoid injuring the lawn. They state further that you should not apply herbicides when temperatures are higher than 95 degrees F. Do not aerate or de-thatch the lawn after applying the pre-emergent herbicide.

Things You'll Need

  • Pre-emergent herbicide granules
  • Spreader
  • Post-emergent herbicide spray

References

  • University of California, Davis: Crabgrass
  • Doityourself.com: Applying Pre-Emergent Herbicide
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About this Author

Victoria Hunter, a former broadcaster and real estate agent, has provided audio and written services to both small businesses and large corporations, worldwide. Hunter is a freelance writer specializing in the real estate industry. She devotes her spare time to her other passions: gardening and cooking. Hunter holds a Bachelor of Arts in English/creative writing.