Crabgrass is one of the most persistent annual weeds plaguing American lawns, spreading rapidly and creating unsightly patches that compete with your healthy turf for water, nutrients, and space. This invasive weed quickly overtakes thin or weakened areas, establishing colonies that choke out desirable grass varieties.
The key to success lies in early intervention – once established, crabgrass becomes increasingly difficult to eliminate. This comprehensive guide will show you exactly how to get rid of crabgrass using 7 proven methods, from manual removal to targeted herbicides.
You’ll also learn prevention strategies that strengthen your turf’s natural defenses against future crabgrass invasions.
What is crabgrass and why is it a problem?
Crabgrass is an annual weed that thrives in warm-season lawn environments. This opportunistic plant spreads in a distinctive crab-like pattern, with a single plant capable of producing up to 150,000 seeds.
There are 2 main types: smooth crabgrass (Digitaria ischaemum) which grows low to the ground with fine leaves, and large crabgrass (Digitaria sanguinalis) which grows more upright with broader leaf blades.
Why is it a problem:
- Thrives in conditions where healthy grass struggles: thin, dry, compacted, or underfed lawns
- Spreads aggressively through massive seed production, creating worse infestations each year
- Competes with desirable turf for water, nutrients, and growing space
- Creates unsightly patches that disrupt lawn uniformity and aesthetics
- Chokes out healthy grass by establishing dense colonies in weakened areas
How do I get rid of crabgrass? (7 proven methods)
Manual removal (for small patches)
Manual removal works best for early-stage crabgrass or small patches before the plant produces seeds. Wait for moist soil conditions, then grasp the plant close to the soil and pull steadily upward to remove the entire root system.
Remove plants during late spring or early summer before they begin seeding. Always bag and dispose of pulled crabgrass.
Never compost or leave on the lawn to prevent reseeding.
Spot-treat with post-emergent herbicides
Post-emergent herbicides target active crabgrass patches, causing plants to die within 7 – 14 days. Chemical options include selective herbicides with quinclorac or fenoxaprop-p-ethyl that won’t harm desirable grass. Organic alternatives use iron-based compounds or selective organic acids.
Apply during mild temperatures (65-85°F) when crabgrass is actively growing. Avoid windy conditions or when rain is expected within 24 hours for best results.
Use a crabgrass-specific herbicide
Selective crabgrass herbicides target only crabgrass without damaging your desired turf. These precision products exploit biological differences between crabgrass and lawn grass varieties, unlike broad-spectrum weed killers that can harm healthy grass.
Look for products containing MSMA (where legal), quinclorac, or mesotrione. Most require 2-3 applications spaced 7-10 days apart for complete control of mature plants.
Natural & DIY crabgrass control options
Natural methods offer environmentally friendly alternatives with reduced safety concerns. White vinegar (10-20% acetic acid) burns down foliage when applied during sunny conditions, though it may require multiple applications and can damage surrounding grass.
Boiling water provides immediate kill for small patches but requires precise application. Corn gluten meal works as a natural pre-emergent, preventing seed germination when applied in early spring before soil reaches 55°F.
Water deeply but infrequently
Proper watering favors desirable turf over crabgrass. Deep, infrequent watering encourages grass roots to grow deeper, creating stronger turf that competes better with weeds while reducing surface moisture that crabgrass needs.
Water 1-1.5 inches per week in 2-3 deep sessions rather than daily light watering. Water early morning (4-6 AM) and ensure penetration reaches 6-8 inches deep.
Improve lawn density
Dense, healthy turf creates natural shade that prevents crabgrass seed germination while competing effectively for nutrients and water.
Overseed thin or bare areas with appropriate grass varieties for your climate – cool-season varieties (tall fescue, perennial ryegrass) for northern regions, warm-season options (Bermuda, Zoysia, St. Augustine) for southern areas.
Time overseeding during peak growing conditions: early fall for cool-season grasses, late spring/early summer for warm-season varieties.
Aerate & dethatch lawn
Soil compaction and excessive thatch create ideal crabgrass conditions while hindering healthy turf growth. Core aeration relieves compaction and improves air, water, and nutrient flow to grass roots. Dethatching removes the dead organic matter layer that harbors weed seeds.
Perform these operations during peak growing seasons when grass can quickly recover. Early fall or spring for cool-season grasses, late spring or early summer for warm-season varieties.
What is the best pre-emergent for crabgrass?
The best pre-emergent herbicide depends on your grass type and regional climate.
For cool-season lawns in northern regions, products containing pendimethalin, prodiamine, or dithiopyr provide excellent 3-4 months of residual control. Warm-season turf in southern climates benefits from pre-emergents with atrazine, simazine, or benefin, which withstand higher temperatures and provide extended control.
Organic options include corn gluten meal and corn-based compounds that inhibit seed germination. While organic products may require more frequent applications, they offer reduced environmental impact and safer use around children and pets.
Application timing is critical regardless of product choice. Apply when soil temperatures consistently reach 50-55°F in spring, typically 2-3 weeks before your area’s average last frost date. This ensures the herbicide barrier is established before crabgrass seeds begin germinating.
When should I treat crabgrass?
Understanding optimal timing for crabgrass treatment maximizes control efforts while minimizing wasted resources. Follow this seasonal treatment schedule based on your region:
| Season | Treatment Type | Activities | For Northern States | For Southern States |
| Spring | Prevention | – Apply pre-emergent herbicides- Create chemical barrier in soil- Focus on problem areas from previous year | Mid to late April | February to March |
| Summer | Active Treatment | – Spot-treat existing crabgrass- Manual removal of small patches- Post-emergent herbicide applications | June – July | May – June |
| Fall | Lawn Repair | – Overseed thin areas- Fertilize appropriately- Strengthen turf density- Prepare for next year | September – October | October – November |
Notes:
- Pre-emergent applications should occur when soil temperatures consistently reach 55°F, often coinciding with forsythia bloom or dogwood flowering
- Early summer treatment is more effective than late summer because younger plants are more susceptible to control measures
- Regional variations can shift timing by 6-8 weeks between northern and southern climates
How to prevent crabgrass from coming back
Long-term crabgrass prevention requires creating conditions that favor your desirable turf while making your lawn less hospitable to weeds. Follow these key prevention strategies:
Annual pre-emergent treatment
- Apply pre-emergent herbicides every spring before soil reaches 55°F
- Create protective barrier that prevents seed germination throughout growing season
- Timing is critical – apply 2 – 3 weeks before average last frost date
Proper mowing practices
- Maintain cool-season grasses at 2.5 – 3.5 inches height
- Keep warm-season varieties at 1 – 2.5 inches height
- Higher cutting creates shade that inhibits crabgrass seed germination
- Use sharp mower blades for clean cuts that promote healthy recovery
- Never scalp lawn – weakened grass creates opportunities for weed establishment
Strategic fertilization
- Follow soil test recommendations for balanced nutrition
- Avoid excess nitrogen that can promote crabgrass growth
- Focus on steady, controlled growth that strengthens turf competitiveness
- Time applications based on grass type and regional growing patterns
Lawn health maintenance
- Water deeply but infrequently to encourage deep root growth
- Overseed thin areas annually to maintain dense turf coverage
- Aerate compacted soil to improve growing conditions for desirable grass
- Address underlying soil issues that create favorable conditions for weeds
Conclusion
Successfully eliminating crabgrass requires combining immediate treatment methods with long-term prevention strategies. The 7 methods in this guide give you multiple options for addressing both existing problems and preventing future infestations.
Early intervention produces the best results with minimal effort and cost. Focus on pre-emergent treatments in spring, treat existing crabgrass in summer, and use fall for lawn renovation. By creating dense, healthy turf through proper care practices, you’ll establish the most effective defense against crabgrass and other weeds.
You can find more from our comprehensive gardening resource center for expert advice and seasonal garden guides.
Frequently asked questions (FAQs)
Will crabgrass go away on its own?
Crabgrass dies with the first hard frost each fall, but the thousands of seeds it produces will germinate next spring, often creating worse infestations. Without intervention, the population typically increases each year.
Is it too late to treat crabgrass in summer?
Summer treatment is still effective, especially in early summer (June-July) when plants are younger and more susceptible. Focus on preventing seed production and plan pre-emergent treatments for the following spring.
Can I apply crabgrass killer and grass seed at the same time?
No. Pre-emergent herbicides prevent all seeds from germinating, including grass seed. Post-emergent herbicides can harm new grass. Wait 4-6 weeks after herbicide application before seeding.
What temperature kills crabgrass?
Crabgrass dies at 25-30°F with the first hard frost. However, seeds remain viable through winter and germinate when soil reaches 55-60°F the following spring.
How do I identify crabgrass vs regular grass?
Crabgrass grows in a distinctive crab-like spreading pattern from a central point, has wider, lighter green leaves with smooth texture, and produces finger-like seed heads. Desirable grasses typically grow upright in clumps or spread underground.
![How much does a yard of topsoil cover? ultimate calculator guide [2025]](https://landscapeunite.com/wp-content/uploads/2025/09/how-much-does-a-yard-of-topsoil-cover-ultimate-calculator-guide-2025.jpg)
