How to Kill Crabgrass in a Lawn

Crabgrass is the bane of any homeowner who wants an attractive lawn. If left alone, crabgrass can quickly spread and crowd out your regular turf grass. There are ways you can control crabgrass in a lawn, but you will need to plan ahead and be persistant.

Difficulty: Moderately Easy

Instructions

1. Crabgrass is a type of grass, so most weed killers designed for lawns won’t kill it. Fortunately, it is an annual, meaning that it dies during the winter and grows again from seed in the spring. The best way to kill crabgrass is to prevent the seeds from germinating.

2. Apply a pre-emergent herbicide to the lawn in early spring to kill the crabgrass before the seeds germinate. Don’t apply the chemical too early, however, or it will not be as effective. A good rule of thumb is to apply the pre-emergent herbicide right after the forsythia bushes stop blooming.

3. If the crabgrass has already started growing, you can apply a post-emergent herbicide. Post-emergent herbicide will kill crabgrass when it is very young, but it may not be as effective on established crabgrass. Follow the directions exactly when you apply post-emergent herbicide or you may end up killing your lawn.

4. Throughout the spring and summer, remove any crabgrass that emerges by hand or spot treat with a general herbicide such as Round-Up. Use a brush to apply the herbicide directly to the leaves of the crabgrass so that it doesn’t get on the surrounding lawn.

5. You can control crabgrass by making sure your lawn is thick and healthy. Mow your lawn at the highest setting to keep sunlight from reaching the seeds. Reseed bare spots promptly before crabgrass takes over.

6. Deny the crabgrass nutrients while keeping your lawn healthy by fertilizing in the fall after the crabgrass has been killed by the frost. Water your lawn less frequently, but more deeply. Your grass has deeper roots so it can get the water it needs, but the shallow rooted crabgrass will experience long dry spells.

Tips & Warnings

• Don’t apply pre-emergent herbicide to a new lawn or it could kill the grass seedlings along with the crabgrass.

Resources

• How to Plant Grass in the Fall
• How to Plant Grass Seed in an Existing Lawn
• How to Choose the Best Grass Seed for Your Yard
• How to Grow a Fall Vegetable Garden
• More Articles by Analana

[edwardvance]

on 9/26/2009 Excellent tips -- will try! 5* and I have recommended you.

[carmensjones]

on 6/29/2009 i hate crab grass. thanks for the tips

[MyJB]

on 6/27/2009 Crabgrass is so annoying. My mother waged war on it every year and weeds, too; of course, she made us kids get in on the action.

[tb711]

on 5/12/2009 Great article. You just reminded me of what I need to go get this week for my lawn.

[juliemcmurchie]

on 5/8/2009 Crabgrass is such a problem. Thanks for the tips on how to get rid of it.