08/20/2026
Heads up, Houston: fall is brown patch season for St. Augustine lawns.
Brown patch — also called large patch — is a fungal disease that flares up when afternoons are still warm but nights begin cooling into the 70s and the humidity stays high. In other words, a typical Houston late-September evening is almost perfect conditions for it. It shows up as roughly circular patches of yellowing, thinning grass that can widen to several feet across, often with a darker ring around the edge.
Here's a quick way to tell it apart from drought stress or grubs: gently tug on a blade inside the affected area. With brown patch, the leaf slips away easily from a soft, darkened, rotted base right near the soil line.
The good news is that a few simple habits go a long way toward prevention:
✅ Water early in the morning only — never in the evening. Grass that stays wet overnight is exactly what the fungus needs.
✅ Ease off high-nitrogen fertilizer heading into fall; lush, fast growth actually feeds the disease.
✅ Improve airflow and drainage — dethatch if your thatch layer is thick, mow at the right height, and avoid overwatering.
Catch it early and your St. Augustine bounces back beautifully once the weather shifts. Want a professional eye on it before it spreads? ABC's Houston lawn care team can diagnose what's really going on and build a fertilization and treatment plan matched to your yard.
