Crabgrass is the bane of homeowners’ existence when it comes to lawn care. This invasive annual weed pops up in spring, spreads rapidly in summer, and pretty much takes over, stealing water and nutrients from your lawn. Getting rid of crabgrass can feel like an impossible task, but with the right techniques and proper timing, you can banish crabgrass for good.
What is Crabgrass and Why You Should Remove it
Crabgrass (Digitaria spp.) is a warm season annual weed that propagates by seed. The seeds germinate when soil temperatures reach 55 to 60°F. The weed thrives in summer’s hot dry conditions. Crabgrass has broad light green leaves that radiate out from a central point, resembling a crab. Hence the name crabgrass.
There are a few reasons why you’ll want to get rid of crabgrass
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It crowds out your lawn grass, stealing water and nutrients.
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If left uncontrolled, crabgrass will produce up to 150,000 seeds per plant, ensuring it comes back year after year.
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It creates thin, bare patches when it dies out in fall.
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Crabgrass provides shelter for other lawn pests like chinch bugs.
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It simply looks unsightly and ruins the aesthetics of a well manicured lawn.
The key is to control crabgrass early, before it goes to seed. Use a combination of preventative measures along with spot treatments.
When to Get Rid of Crabgrass
Timing is everything when it comes to controlling crabgrass. Follow this yearly schedule:
Spring
Apply pre-emergent herbicide in early spring before soil temperatures reach 55°F. This prevents seeds from germinating. Do this around the time forsythia blooms.
Hand pull small crabgrass plants as they start to appear. Make sure to get the entire root.
Spot treat young crabgrass plants with post-emergent herbicide. This kills newly sprouted crabgrass.
Summer
Continue hand pulling crabgrass plants, especially before they produce seed heads.
Spot treat with post-emergent herbicide as needed through early summer. It becomes less effective as plants mature.
Maintain healthy turf with proper mowing, watering, and fertilization to crowd out crabgrass.
Fall
Overseed bare spots left by dead crabgrass so desirable grass fills in those areas. The best time is late August to early September.
4 Ways to Get Rid of Crabgrass
1. Use Pre-Emergent Herbicide
Applying pre-emergent herbicide is the number one way to control crabgrass. This must be done in early spring before the seeds sprout. The herbicide forms a barrier that prevents the seeds from germinating.
Look for active ingredients like prodiamine, dithiopyr, or pendimethalin. Apply according to label instructions. Reapply if heavy rains occur.
One application may not be enough for severe infestations. Split applications, one in early spring and one 4-6 weeks later, provide season-long control.
2. Pull Crabgrass by Hand
For light infestations, hand pulling crabgrass is an effective organic control. Use a weeding tool and grasp low and pull slowly to remove the entire root. Dispose of the weed properly so it doesn’t spread.
Be cautious pulling large or mature plants as they may leave bare patches when their deep roots rip out grass. It’s best to hand pull young crabgrass.
3. Spot Treat with Post-Emergent Herbicide
Post-emergent herbicides selectively kill crabgrass after it sprouts. Spray it directly on the weed. Look for active ingredients like quinclorac, fenoxaprop, and mesotrione.
Repeat applications are likely needed. Post-emergent herbicides become less effective as the crabgrass matures. Only use this method to spot treat young crabgrass.
4. Improve Lawn Health
A dense, vigorous, healthy lawn is your best defense against crabgrass. Follow these tips:
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Mow high – between 3-4 inches tall. This shades out germinating weeds.
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Fertilize in fall – avoid spring. Fertilizing in spring actually helps crabgrass.
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Water deeply and infrequently. Crabgrass has shallow roots.
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Overseed bare spots in fall.
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Aerate compacted areas.
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Keep grass thicker by mowing regularly.
When Not to Control Crabgrass
There comes a point where it’s best to stop trying to control mature crabgrass that’s gone to seed. The seeds have already spread. Pulling at this point just disturbs the soil and brings more seeds to the surface.
Likewise, don’t use post-emergent herbicides on large, mature crabgrass. It’s not effective at that stage. Just ride it out, let the plant die off with the frost, and be prepared to eradicate next year’s crop.
Focus on pre-emergence in spring, and improving lawn health and thickness to prevent future crabgrass infestations.
Crabgrass Prevention Tips
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Time pre-emergent herbicide applications for early spring when soil is around 55°F.
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For severe infestations, split pre-emergent applications – early spring and 4-6 weeks later.
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Hand pull young crabgrass plants.
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Spot treat small crabgrass plants with post-emergent herbicide.
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Mow high – 3-4 inches tall. Never scalp the lawn.
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Fertilize in the fall to thicken turfgrass. Avoid spring fertilization.
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Water deeply and infrequently.
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Overseed bare spots in late summer.
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Aerate compacted soil.
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Keep turf thick by mowing regularly.
Vigilance and proper timing are key to preventing crabgrass. But don’t worry – with a good preventative program, you can rid your lawn of this invasive weed for good. Just be prepared for the long haul as it may take a couple of seasons to deplete the seed bank. But soon you’ll be crabgrass free and ready to enjoy a lush green lawn.
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How to Get Rid of Crabgrass (4 Easy Steps)
FAQ
What will kill crabgrass but not your lawn?
Actively growing crabgrass in your lawn calls for selective, post-emergent herbicides, such as Image All-In-One Lawn Weed Killer or Image Herbicide Kills Crabgrass, that kill crabgrass and leave your lawn grass untouched.
How do you permanently get rid of crabgrass?
Post emergent crab grass can be eradicated with Quinclorac or Tenacity, but you also need a good pre emergent strategy. Granular or liquid Prodiamine will prevent the majority of the crabgrass from ever growing in the first place.
Does vinegar kill crab grass?
Gardening vinegar.
This all-natural method to kill crabgrass is a great option that won’t cause lasting soil damage. Simply spray the vinegar (5 percent acidity or higher) on the weed until it’s drenched. Repeat a few times over several days to a couple of weeks or until the crabgrass dies.
Does mowing crabgrass spread it?
How do I get rid of crabgrass?
Luckily, there are some quick and easy ways to remove crabgrass and keep it at bay. From non-chemical and chemical treatments, to simply lawn maintenance, these can all help to keep your lawn weed-free all year round.
How do I prevent crabgrass from germinating?
a) BEFORE crabgrass emerges: Obviously, it is best to prevent crabgrass before it germinates. This means “pre-emergent” herbicide spray. If you read this article AFTER crabgrass has emerged, you should still address prevention next year.
How do you mowing crabgrass?
Check the recommended mowing heights for your type of grass and cut your lawn at the highest recommended setting. Crabgrass requires plenty of light to germinate, so keep the grass as thick and long as possible to create shade near the soil surface. Cutting your lawn too close will produce patches where crabgrass and other weeds can germinate.
Does crabgrass take over your lawn?
Crabgrass will take over your turf, preventing your lawn from receiving nutrients it needs to in order to grow healthy grass. This guide will teach you how to get rid of crabgrass and prevent it from returning to your lawn.
How do I stop crabgrass from sprouting on my lawn?
Shredded leaves, grass clippings, or straw work better as weed deterrents with a separating layer of newspaper or cardboard between them and the soil. To prevent crabgrass from sprouting on your lawn, apply a preemergent weed killer made from corn gluten meal in the spring, two weeks before your last expected frost.
How do you keep crabgrass and weeds away?
A healthy lawn will keep crabgrass and weeds at bay. This is a good time to inspect your lawn for bare spots that need to be addressed. Leave your grass on the tall side, about three inches long. Taller grass blades help shade the soil. Leave grass clippings behind to add natural nutrients and shade for the soil.