How do you kill CRABGRASS without hurting the rest of your lawn ?

9 Answers

  • 1 decade ago
    Favorite Answer

    Crabgrass is notoriously difficult to kill -- and to keep from reemerging the next growing season.

    I've been fighting it for years under the oft-mistaken impression that doing so is a productive way to channel my agressions. However, if you take one season off -- just one -- you'll have to start all over again.

    You can kill the plant -- it even dies off over the winter, because crabgrass is an annual -- but the seeds remain to do their damage when summer comes around again.

    (In fact, if it were a perennial -- and didn't turn brown and die in the frost -- and if it came up in the early spring -- like the rest of the grass -- I'd probably cultivate it instead of killing it. The damn stuff grows almost anywhere. It's tolerant of bright sun, deep shade, heat, drought, heavy rain. It makes an almost perfect lawn, except it turns brown in the winter and then leaves a bare spot until June or July.

    Here's my plan of attack for this year and next:

    1. Right now, with a large section of lawn completely given over to crabgrass, do nothing. At least it's green, and it's difficult to grow regular grass when the weather is hot. Try to mow before those three-pronged seed stalks mature to reduce problems later on.

    2. About six or seven weeks before the first frost, kill the crabgrass. You can purchase crabgrass spray that won't hurt your lawn at your local hardware store. You may need a few applications.

    3. If you don't start seeing results in a week or so, you may need more potent stuff. Try some Roundup. It kills just about everything that's green. Concentrate on the crabgrass, but don't worry if you spray some of the grass around the edges. (Use the regular Roundup, not the new "advanced" variety, or nothing will grow there until next year. With the regular Roundup, you only have to wait a couple of days before replanting.)

    4. Once the crabgrass turns brown, pull it up. Make sure you get any living crabgrass that remains, since crabgrass tends to spread out. One plant can reinfest a large section of lawn. And pull up any regular grass around the edges, if it looks dead or dying (from the Roundup).

    5. When you're down to the bare dirt, dig it up a quarter inch to a half inch deep. If the ground is dry, you might want to moisten it a bit first. A rake works, but you have to press down hard. You don't want to spread your new grass seed on top of the ground and just leave it there.

    6. Get a high-quality, brand-name grass seed -- or a lawn patch kit. Again, your local hardware store should have plenty. If you use only grass seed, add a little starter fertilizer, spread the seeds out evenly by sprinkling them with your hand (or with a small mechanical spreader), and rake the dirt over them. If you get a lawn patch kit instead, you won't need fertilizer; it comes in the same bag as the seeds. (You'll probably have to spread the patch kit -- seeds, fertilizer and, sometimes, mulch -- by hand.)

    7. Water according to the directions that come with the seeds. This is a commitment you have to be willing to make, especially if you don't have an automatic sprinkler system. You should water at least twice a day and keep the seeds moist -- not drenched -- all the time. The new grass should start growing in 10 days to two weeks. Keep watering -- and don't mow until the new grass is about two inches high. If you're having a dry fall, continue to water the new grass every couple of days until it stops growing for the season.

    8. HERE'S THE IMPORTANT PART. In the early spring, when the grass first starts to grow, find fertilizer with crabgrass preventer. You can apply it to the whole lawn, but you should definitely apply it to the new grass -- and for several feet around the new grass -- to make sure the crabgrass seeds that lay dormant all winter don't sprout. A good one is Scotts Lawn Pro -- Step 1 for Seeding Starter -- Fertilizer Plus Crabgrass Preventer. (I don't work for Scotts, btw.) This is the part I always neglect until the crabgrass starts taking over my lawn.

    9. During the summer, keep on the lookout for new crabgrass growth. When you see some starting (and you will) pull it out or give it a good treatment with crabgrass killer. If the new grass is well established, you shouldn't have much trouble.

    10. Enjoy your lawn.

    Hope this helps.

  • 1 decade ago

    The quick and dirty!!

    Apply a preemergence (yes, a PRE-emergence) herbicide once in the fall then again in the spring. This will prevent any of the crabgrass seeds from germinating.

    In the dormant season, pull the crabgrass out by hand (it is easier to see the crabgrass in contrast to St. Augustine-- in FL anyway!). Make sure you get ALL of the pieces. Any little piece left will root and grow, then the problem starts all over again!

    If you have large patches, I would suggest treating the area with roundup and resodding. I know this sounds drastic, but there aren't any postemergence herbicides that will selectively remove crabgrass out of other grasses. (There used to be a product on the market called asulox, but the manufacturer took it off.) Preen is glyphosate, whic is the same active ingredient in RoundUp. ( It will provide suppression (partial control) of crabgrass because it is a broad spectrum herbicide. Just be careful when applying products to plants you want to keep! Follow the label.

    You must be diligent in this quest to remove crabgrass from your yard! It will be an ongoing process!

    Oh, and always clean off your mower and mow the crabgrass areas in your yard last. The clippings from the mower can be spread through your lawn, so you can distribute the weed all over the place!!

    Source(s): Doctor of Plant Medicine
  • 4 years ago

    How To Kill Crabgrass

  • Anonymous
    6 years ago

    This Site Might Help You.


    How do you kill CRABGRASS without hurting the rest of your lawn ?

    Source(s): kill crabgrass hurting rest lawn:
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  • 1 decade ago

    Go to your local garden center or home center( Lowes,etc.)and

    ask for a "post-emergence" weed killer.It is a selective herbicide

    which means it won't harm your turf grasses.Don't get

    Round-Up as that will kill everything(non-selective herbicide).An

    example of a post-emergence herbicide is Trimec or Vantage.A

    little bit goes a long way. Next spring you might also want to apply

    a pre-emergence herbicide such as Surflan or Atrazine.Read

    instructions carefully.Last,but not least,you could call Chem Lawn.

  • 1 decade ago

    Try the site below -- 10 steps to become crabgrass free -- maybe it has some tips that will help you. We've just let ours go back to clover!! The bees love us. lol!! Good luck!!

  • Apply Preen in early spring before the seeds germinate. Preen & Green will also fertilize the grass while it kills the weeds.

    Source(s): Lawn and Garden siminars.
  • ?
    Lv 5
    1 decade ago

    hire Chemlawn and let them figure it out.......

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