Brown Patches in Your Florida Lawn: What's Actually Causing Them

Fungus, chinch bugs, dry sprinkler zones, or dog spots — Florida brown patches have four usual suspects. How to tell them apart before you treat the wrong one.

Every brown patch looks the same from the driveway. Up close, they're four different problems with four different fixes — and treating the wrong one wastes a season.

1. Brown patch fungus (the circles)

Roughly circular patches that show up in the cooler, wetter months, often with a yellowish ring at the edge. The grass pulls up easily at the base like a loose tooth. Fungus loves lawns watered at night — the blades sit wet for 12 hours. Fix the watering schedule first, then treat.

2. Chinch bugs (the spreading burn)

Summer, full sun, usually starting near driveways and sidewalks where the soil runs hottest. The patch looks drought-stricken but doesn't green up after watering — because the bugs are drinking the plant, not the soil. Part the grass at the green/brown border and look for tiny black bugs with white wing marks.

3. Irrigation gaps (the geometry)

If the brown area has a suspiciously straight edge or a crescent shape, stop diagnosing diseases and go run your sprinklers. A stuck head, a clogged nozzle, or a zone that lost pressure paints dry geometry on the lawn. This is why an irrigation eye-check is point 6 of our 9-Point Golden Cut — a $4 nozzle catches what looks like a $400 problem.

4. Pet spots (the dark ring)

Small, concentrated, often darker green around the edge (nitrogen ring). Flush with water; re-sod the center if it's dead dead.

The honest answer

Most "mystery" brown patches are two problems stacked — a dry zone that stressed the grass, then bugs or fungus that moved in on the weakened area. If your crew's diagnosis is always "needs more water," get a second opinion.