Plant Problem Diagnostic
How to Identify and Control Crabgrass
The short answer
Crabgrass (Digitaria spp.) is a summer annual grassy weed with a prostrate, spreading habit, wider yellowish-green blades, and stems that branch and creep across the ground. Seeds germinate in spring once soil stays above about 55F for several days, plants grow through summer, set thousands of seeds, and die at the first fall frost.
Because it is an annual that invades thin, weak turf, the most reliable cultural control is a dense, competitive lawn. Mow at the recommended height for your grass, water deeply but less often, fertilize appropriately, and overseed bare spots so crabgrass has no opening.
How to identify crabgrass
- Low, spreading (prostrate) stems that branch and root outward
- Wider, coarser blades than lawn grass, yellowish-green color
- Summer annual: appears in spring, thrives in heat, dies at frost
- Reproduces only by seed, which stays viable in soil for years
Cultural and physical control
Favor the lawn over the weed. Raise mowing height, water deeply and less frequently, keep nitrogen fertility adequate, and aerate compacted soil so turf roots stay vigorous. Hand-pull or dig young crabgrass plants before they set seed, and reseed thin areas so desirable grass fills the gaps.
When to escalate
If crabgrass keeps returning despite improved lawn care, or the infestation is too large to manage by hand, escalate your plan. For chemical options and the correct timing for your region, consult your county Extension office.
→ For chemical control options, contact your local county Extension office for products and timing suited to your lawn and area.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- University of Minnesota Extension — Managing weeds in lawns — Cultural practices (mowing height, watering, fertility, aeration) favor turf over weeds; crabgrass invades thin lawns
- North Dakota State University Extension — Crabgrass Management — Summer annual, prostrate habit, germinates above 55F, seeds spring to late summer, thousands of viable seeds, dies at frost