How and when to kill weeds in your lawn
Start by identifying the weed, since broadleaf weeds, grassy weeds and sedges need different approaches. A thick, well-mowed lawn is the best long-term control. Many broadleaf weeds are easiest to control in fall; crabgrass prevention happens in early spring.
Identify first
Dandelion and clover are broadleaf weeds. Crabgrass is a grassy annual. Nutsedge looks like grass but has triangular stems. Fescue Rescue's Weed ID can help you narrow it down from a photo.
Cultural control
Mow tall fescue around 3–4 inches, water deeply and infrequently, and overseed thin spots. Hand-pull small patches when practical.
If you use a product
Choose one labeled for tall fescue and your specific weed. Follow its temperature, wind, rain-free and reseeding limits exactly. Do not treat newly seeded areas unless the label allows it.
Weather timing
Avoid spraying in high wind, in high heat, or before rain within the label's rain-free window. Fescue Rescue checks your local forecast for those conditions — but the product label decides.
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Rescue my lawnEducational guidance only. Local rules and product labels control; a soil test is more reliable than general advice.