How to Control Crabgrass

Ask Julie Answers, Lawn Care, Lawn and Garden by Julie Day

“How do I get rid of crabgrass? I have tried all the over the counter products, and I can’t seem to get rid of it.” -Dusty

To kill crabgrass, there are two things you need to know about it:

  1. It’s an annual weed: The plants themselves are killed by fall frosts, but the seeds remain on the ground to sprout anew the next spring and summer. Each plant can produce over 150,000 seeds!
  2. It’s a grassy weed: As the name implies, crabgrass is a grass as opposed to a broadleaf weed. That means that any product that kill crabgrass will also kill the grass in your lawn.

Knowing these facts, keep in mind these tips for controlling crabgrass:

  • A healthy, thick lawn is your first defense. Nurture your lawn, and keep your mower on the highest possible setting. Crabgrass seeds require bright sunlight to germinate, so they’re more likely to invade bare spots.
  • Water less frequently, but more deeply, to discourage weed germination.
  • Use a grass catcher when mowing, to capture seed heads. Discard the clippings – you can begin composting them again once you’ve got the crabgrass under control.
  • Use a pre-emergent herbicide in the spring and summer to prevent the seeds from germinating. Do not aerate or otherwise disturb the “shield” provided by the herbicide. Watch forsythia and lilac bushes, since the traditional time to apply pre-emergent herbicide is between the blooming of forsythia and lilac. You may also want to re-apply the herbicide in early summer.
  • “Weed and feed” type products often contain pre-emergent herbicides, but some do not have high enough concentrations to be effective on stubborn crabgrass. If you’ve tried them without success, consider applying a pre-emergent herbicide separately.
  • Attack clumps of crabgrass as soon as you spot them, before they have a chance to go to seed. Crabgrass produces a toxic chemical that inhibits the growth of plants around it, so it will soon start affecting your lawn grass. Pull the plants by hand, or spot spray with a post-emergent herbicide such as Round Up.
  • Pull and discard the dead plants as soon as possible, to prevent them from smothering your lawn grass.

Further Information

Julie

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3 Comments on “How to Control Crabgrass”

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  1. CAROL Says:
    December 10th, 2008 at 16:04

    What a worthless article. It could not be read because the formatting cut off the right hand side of the ariticle.
    Fix this please as I need this advice. thanks

  2. Carol Says:
    December 10th, 2008 at 16:05

    Well, after I left the first comment, then the article could be read… sigh.

  3. Julie Day Says:
    December 10th, 2008 at 20:02

    I’m glad you were able to read the article. If you have any more trouble viewing articles or following links, please post a comment or click the “Ask Julie” link to send an email.

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