Lawn with brown patches next to healthy green grass

Lawn Brown Patches: Causes & Fixes

Grin's Irrigation LLCFebruary 19, 20266 min read

Cause 1: Irrigation Coverage Gaps

Brown patches in consistent locations usually mean clogged nozzles, misaligned heads, broken heads, or pressure loss. Run each zone and watch where water lands. A system audit can identify and fix gaps in one visit.

Cause 2: Compacted Soil

Widespread brown areas in high-traffic zones. Minnesota's clay soil compacts easily, preventing water and air from reaching roots. Fix: core aeration, ideally in September.

Cause 3: Grub Damage

Irregular brown patches that feel spongy and lift up like carpet. White grubs feed on grass roots. If you find more than 5–10 per square foot, treatment is needed.

Cause 4: Lawn Disease

Circular brown patches with a darker border ring. Brown patch (Rhizoctonia) thrives in hot, humid weather. Fix: water early morning only, reduce nitrogen, and consider fungicide for active outbreaks.

Cause 5: Dog Urine Burns

Small round brown spots with a dark green ring. High nitrogen in urine burns grass in concentrated spots. Rinse affected areas immediately after use; rake, topsoil, and overseed existing burns.