How to get rid of crabgrass in your lawn
Here’s how to get rid of crabgrass: pull or spot-treat young plants in late spring and early summer, let frost kill the survivors in fall, and stop next year's crop with a pre-emergent applied before the soil reaches about 55 °F. Because crabgrass is an annual that comes back only from seed, preventing those seeds from sprouting is the real fix.
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Crabgrass is one of the most common lawn weeds in the country, and also one of the most predictable. It sprouts on schedule every spring, spreads only by seed and dies every fall. Once you know its calendar, you can beat it in two or three seasons.
How do you identify crabgrass?
Crabgrass is a light green, coarse grass that grows low and wide in clumps, sprawling outward from a center like the legs of a crab. Two species dominate US lawns:
- Large (hairy) crabgrass has hairy leaf blades and sheaths. Its stems can root where they touch the ground, so one plant covers a surprising area.
- Smooth crabgrass has mostly hairless blades and stays smaller and lower.
In mid to late summer, both send up thin seed heads that split into several finger-like spikes. The plants turn purplish or brown after the first frost and die, leaving bare patches.
Crabgrass look-alikes
Not every coarse grass is crabgrass, and the look-alikes need different treatment. Goosegrass has a flattened, silvery-white center and thrives in compacted soil. Foxtail grows more upright and produces bristly, cylindrical seed heads. Tall fescue and quackgrass are perennials: they are already green in early spring, before crabgrass sprouts, and they survive the winter. A clump that is green in March is not crabgrass, and no crabgrass product will remove it.
Why does crabgrass take over a lawn?
Crabgrass seed needs light and warm soil to germinate. It wins wherever sun reaches bare ground: thin turf, lawns mowed too short, south- and west-facing slopes, and strips along driveways and sidewalks where pavement heats the soil. Light, frequent watering helps it too, because it keeps the top inch of soil moist for shallow-rooted seedlings while lawn grass roots stay short. Seeding a lawn in late spring is another classic trigger, since the bare soil is ready just as crabgrass starts to sprout.
How to kill crabgrass that is already growing
Pull it while it is young
Hand removal is the simplest crabgrass removal method for small patches. Water the area first, grip the plant at its base and pull slowly so the fibrous roots come out with it. Young plants of a week or two come out easily; older ones that have rooted at the nodes take more work, and a hand weeder helps. Bag plants that have seed heads. Then fill the hole with soil and a pinch of grass seed in spring or fall.
Use a post-emergent herbicide labeled for crabgrass
Several active ingredients kill crabgrass but not grass when used on the turf types listed on their label:
| Active ingredient | Best on | Notes |
|---|---|---|
| Quinclorac | Young and more mature crabgrass | Also controls some broadleaf weeds. Labeled for many cool-season grasses, bermudagrass and zoysia; not St. Augustine. |
| Fenoxaprop | Plants up to about 4 to 5 tillers | Can injure some Kentucky bluegrass in high heat; avoid on drought-stressed lawns. |
| Mesotrione | Plants with fewer than 4 tillers | Treated weeds turn white before dying. Usually needs repeat applications. Not for fine fescue. |
| Topramezone | Plants with fewer than 4 tillers | Also whitens weeds; controls goosegrass and foxtail. |
| Dithiopyr | Seedlings up to one tiller | A pre-emergent that also kills very young crabgrass, useful when you are a little late. |
In the South, St. Augustine and centipede lawns have fewer options; atrazine is one ingredient labeled for them. Whatever you use, spray on a calm day when temperatures will stay below about 85 °F, on moist soil and actively growing plants, and follow the label rate and repeat interval. In northern lawns crabgrass keeps germinating into midsummer, so an early spray may need a follow-up.
Small plants die, big plants laugh: every crabgrass product works best on young plants. Once a clump has spread into many tillers in August, it is usually better to pull the worst ones, let frost do the rest and focus on prevention.
How to prevent crabgrass next year
A pre-emergent herbicide is the most reliable crabgrass control there is. It forms a thin barrier in the top layer of soil that kills seedlings as they sprout. Put it down a little before crabgrass germinates: when soil at about 2 inches deep approaches 55 °F for several days in a row. Forsythia dropping its petals or redbud starting to bloom are handy local signals. That is roughly late winter in the Deep South, March to April in the transition zone and April to early May in the North. Our weed control calendar gives the month for your region.
- Choose an active ingredientProdiamine, dithiopyr and pendimethalin are the most widely used for lawns; benefin and bensulide are older options. If you might be late, dithiopyr also kills crabgrass seedlings up to the one-tiller stage.
- Apply evenly at the label rateUse a spreader for granules or a sprayer for liquids, and do not skip the hot edges along pavement.
- Water it inMost products need about half an inch of rain or irrigation within a few days of application to activate. Check your label for the exact window.
- Consider a second applicationMany pre-emergents last 6 to 12 weeks. Where crabgrass keeps sprouting into summer, labels often allow a split or second application to stretch control.
Most pre-emergents also stop grass seed. If you must seed in spring, use one of the products labeled for use at seeding (siduron or mesotrione); otherwise, prevent crabgrass in spring and seed in late summer or early fall.
How to get rid of crabgrass naturally
- Hand pulling young plants, every week or two from late spring to midsummer.
- Corn gluten meal is an organic pre-emergent, applied at the same timing as synthetic products. Results are less consistent; it tends to improve after two or three years of use, and it adds nitrogen. It also stops grass seed.
- Mowing high is the cheapest crabgrass preventer: 3 to 4 inches for most cool-season lawns, and the high end of the range for warm-season grasses.
- Deep, infrequent watering of about an inch a week instead of a daily sprinkle.
- Fall overseeding of thin areas, so there is no bare soil left in spring.
Avoid boiling water and strong vinegar in the lawn: both kill the surrounding grass and leave a bare spot that crabgrass will reclaim. Our natural weed killer guide explains where those methods do make sense, such as crabgrass in driveway cracks.
Common crabgrass mistakes
- Applying a pre-emergent after crabgrass is up: it will not kill it (except dithiopyr on tiny seedlings).
- Forgetting to water in a pre-emergent, or seeding the lawn a few weeks after applying one.
- Using a broadleaf weed killer on crabgrass: products for dandelions and clover do not touch grassy weeds. Our lawn weed killer guide explains which product does what.
- Mowing at 2 inches or less in summer, which lets sun reach the soil.
- Spraying big, seeding crabgrass in August instead of preventing it in April.
FAQ
What kills crabgrass but not grass?
Grass-selective herbicides labeled for crabgrass: quinclorac, fenoxaprop, mesotrione and topramezone kill young crabgrass in most established lawns, and dithiopyr kills it until it reaches the one-tiller stage. Each one is safe only on the grass types listed on its label. Mesotrione, for example, is not labeled for fine fescue, and quinclorac is labeled for bermudagrass and zoysia but not St. Augustine.
Will crabgrass die in the winter?
Yes. Crabgrass is a summer annual, so every plant dies with the first hard frost and leaves a brown gap in the lawn. The problem is the seed it dropped in late summer, which sprouts next spring when the soil warms. That is why a spring pre-emergent and a fall overseeding matter more than chasing the dead plants.
Is it too late to kill crabgrass in late summer?
Mostly, yes. By August the plants are large, heavily branched and already setting seed, and most products work poorly on them. Pull the worst patches before the seed heads ripen, let frost finish the rest, overseed the gaps in early fall and plan your pre-emergent for next spring.
Does pulling crabgrass work?
Yes, on young plants and small patches. Pull from the base after watering so the fibrous roots come out, and bag any plant with seed heads. Fill the hole with soil and grass seed, or it will be reclaimed by new crabgrass.
Can I seed my lawn after putting down crabgrass preventer?
Not with most products: prodiamine, dithiopyr, pendimethalin and similar pre-emergents stop grass seed too, and labels give waiting periods of several weeks to months. Siduron and mesotrione are exceptions labeled for use at seeding. Otherwise, use the pre-emergent in spring and seed in late summer or early fall.
Does vinegar kill crabgrass?
Household vinegar burns the leaves of young crabgrass but rarely kills it, and stronger horticultural vinegar (around 20% acetic acid) kills the lawn grass it touches as well and can burn skin and eyes. In a lawn, pulling or a selective product is the better choice.
Related
- Lawn weedsCommon lawn weeds by type (grassy, broadleaf, sedge), what each one says about your lawn, and the right control and timing to get rid of weeds in grass.
- Pre-emergentA pre-emergent herbicide stops weed seeds before they sprout. Which active ingredient to choose, when to apply it by region, and how to water it in.
- FoxtailHow to get rid of foxtail grass: identify the type, pull it before seed heads ripen, use the right pre-emergent and post-emergent, and protect your dog.
- Weed control calendarThe best time to spray weed killer by weed, season and region, plus the weather rules on the label. Pick your region for this month's lawn to-do list.
Updated October 3, 2026