LawnSuite guide: Brown patch in lawns: how to spot it and fix the conditions
Use this LawnSuite guide to recognise the problem before deciding what to do. Brown patch makes large, irregular brown rings, usually after hot, humid weather and wet nights. Buffalo lawns in a humid summer are the classic case.
How to spot it
Larger, irregular brown rings or circular brown areas. Look early in the morning: some fungal diseases show fine, cobweb-like threads on the dew. Leaves dying from the tip point to disease. Whole plants gone at the roots point to grubs or dry patch instead.
When it shows up
Hot days above about 28 °C, warm nights above about 15 °C, and leaves that stay wet for more than about 10 hours. Humid summer weather and evening watering set it up.
Your grass type
Buffalo: the classic warm-season case in humid weather. Couch: less common than in buffalo. Cool-season lawns: a summer disease, made worse by summer nitrogen and overwatering. Zoysia: watch for large patch instead, which is a separate disease.
Fix the conditions first
Water in the morning, never in the evening; a canopy that stays wet overnight feeds brown patch. Water deeply and less often rather than a little every day. Mow with sharp blades and reduce thatch. On cool-season lawns, don't feed nitrogen through summer.
If you use a product
If it keeps spreading after you've fixed the conditions, use a turf fungicide whose label names brown patch and your turf type, and follow the label. Different diseases need different products, so identify it first.
Keep reading
Not sure it's brown patch?
Create a free LawnSuite account in your browser and photograph the patch. Photo diagnosis uses Google Gemini vision to identify the likely weed, pest or disease and shows a confidence score for each result, so you can match it to the signs on this page before you treat.