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Crabgrass control in Bermuda lawn

My front lawn is all bermudagrass. This is my second year of paying attention to good cultural practices, so it's still coming up to speed. Right now I have a number of large patches of very dense crabgrass, and I was wondering what I can do to control it. I live in Durham, NC, so the temps are already quite hot and I understand that chemical options right now are fairly (extremely?) limited. Is there anything I can apply in the summer? How about the early fall when things cool off?

I also understand the easiest way to control it, besides extremely dense, healthy grass, is to get a good pre-emergent shield down. I applied Dimension this spring March 15, shortly after the forsythia was blooming. I'm thinking this may have either been too late this year (we had a cold late winter that transitioned over night into a warm early spring), or maybe I applied too little (about 6 pounds per thousand square feet, maybe a little too light).


Comments (12)

  • 10 years ago
    last modified: 10 years ago

    Buy some Drive XLR8 (Quinclorac) and broadcast spray your lawn with it. Then use a round of Dimension or other pre-emergent right after. This will kill the actively growing crabgrass and throw down a prevention barrier. Use a high rate of the Dimension so you can control it for 8 months. Just apply the pre-emergent 2 times per year and never have crabgrass again. Keep the Drive XLR8 around for spot treatments as needed.

    You are lucky you have Bermuda grass; it's extremely easy to maintain that turf.


    PS: Your application of Dimension was too late for NC. You should be applying it when ground temp is 55F at the latest. I applied my pre-emergent March 15 and I'm in MD. It's OK to be a bit early with the pre-emergent it lasts so long.

  • 10 years ago

    You're right about good cultural practices. Now define your good cultural practices. (didn't know there would be a quiz, did you?) I just want to see if there's something else we can suggest to tune up your good practices.


  • 10 years ago

    That sounds good to me. Some people make their own weed problems by not mowing bermuda low or by watering too frequently.


  • 10 years ago

    Bah, I have been pulling it for 30 minutes every day, but its freaking everywhere on half the lawn and starting to make a lot if very dense clumps. It will likely be September before it's under 85 and I can spray quinoclorac...

  • 9 years ago

    Spray anyway you have Bermuda, it's the devil and can't be killed


  • 9 years ago

    Is another round of Dimension suggested now, in the summer? I usually put down an early spring and a mid fall application (to prevent the horrible winter annuals that are super common here).


    I got some Quincept and sprayed the lawn once - it seems to be working well. Hopefully in a few more days (14 days after) we'll get a decent weather window again and I can apply the second treatment.

  • 9 years ago

    I'd put dimension down either 2 or three times a year to ensure effective prevention. You can apply a pre-emergent at anytime just plan it out so you have good coverage depending on various weed germination time frames.

  • 9 years ago

    If you have it in dense clumps you can dust baking soda on just the crabgrass. It will turn black and die in about 48 hours. Be careful because if you get the baking soda on the bermuda it will likely die, too, but here's the process. But as mentioned, it is the antichrist and will come back.

    You'll need simple baking soda, a sock or stocking (new or used but no holes), spray bottle, water, shampoo, and molasses. Crabgrass is hydrophobic so in order for the baking soda to be effective it needs to stick to the blades of the grass. That's what the water, soap, and molasses are for. Spray the weed with water and notice that the water beads up. Add the right amount of soap and/or molasses to the water and the water will not bead up but will stick to the blades. Start with a few drops of both molasses and shampoo in a pint spray bottle. Spray and see if you have enough sticker stuff. Experiment until you get enough. Then put a fistful of baking soda into the sock/stocking. Spray the weed and dust it with baking soda. Squeeze, pinch, or punch it out of the sock/stocking. Apply liberally. When the moisture dries the crabgrass should look like it's covered in baking soda. Don't inhale the dust or get it in your eyes. It will change the pH of your innerds and irritate the heck out of you for longer than is comfortable. It doesn't exactly die before your eyes, but if you come back in an hour it should look significantly worse. The black slimy look in 48 hours is very satisfying.

    Once it is out, I would dust some compost on the area to reestablish the soil microbes. Baking soda is a broad spectrum antifungal agent. Actually I suspect that is the mechanism that causes the plant to die is by wiping out the protective fungi that live on the blades of crabgrass and other grasses.

  • 9 years ago

    >>Actually I suspect that is the mechanism that causes the plant to die is by wiping out the protective fungi that live on the blades of crabgrass and other grasses.

    Interesting point.

    You just mixed what's basically a slurry of the stuff in water, soap, and molasses--so we can safely call it a fully saturated solution, I think.

    It's definitely going to slaugher the fungal associations on the leaves wholesale. Bacteria aren't going to be happy, either, due to the sodium levels.

    The pH of baking soda will range from 9 (1 molar solution) to 10.5 (fully saturated), so this should be 10.5.

    That's entirely high enough to destroy the waxy coating on the leaves by turning it to soap*.

    Once that happens, the leaf has no protection from mechanical damage, further chemical damage from the very alkaline paste, and from water loss to the atmosphere. Cells die. Followed by the plant as a whole.

    * Soap is usually made from sodium hydroxide, but any alkaline will do (historical soap making used potash). The process is just slower with lower pH items and more of the item is required to make soap.

  • 9 years ago

    Thanks for the suggestions. I hit it with a second dose of Quincept today, 4 weeks ( too long but temps were too high) after the first. I may hand pull the huge clumps in a few weeks but we have a new baby and who has the time?

  • 9 years ago

    A satisfying sight:

    Quinoclorac on crabgrass.

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