If you’ve noticed circular brown patches suddenly appearing in your lawn this summer, you’re not alone. Brown Patch (Rhizoctonia solani) is the number one turf disease in Middle Tennessee, and it can take over a healthy-looking lawn fast.
Why Brown Patch Is Always a Threat Here’s the tricky part: the fungus that causes Brown Patch actually lives in your soil year-round. It doesn’t need to “arrive” because it’s already there waiting for the right conditions to activate. Once those conditions align, an otherwise healthy lawn can decline in a matter of days.
The Three Conditions That Trigger Brown Patch
- Warm nights and hot days: Nighttime temperatures in the 70s combined with daytime highs in the mid-to-upper 80s create ideal conditions for fungal growth.
- Excessive moisture and prolonged leaf wetness: Heavy rain, overwatering, poor drainage, or watering late in the day can keep grass wet for 10-12+ hours. Late afternoon or nighttime irrigation is one of the most common, and most preventable, mistakes homeowners make.
- High humidity: Humidity above 90% is often the final trigger that lets Brown Patch spread quickly.
Signs to Watch For Brown Patch typically shows up as circular brown patches with a darker outer ring, sometimes called a “frog eye” pattern. You may also notice blighted grass blades with tan to brown lesions, general thinning across affected areas, and rapid expansion of patch size once conditions are favorable.
How to Reduce Your Risk A few simple habits can make a real difference:
- Keep mower blades sharp; dull blades tear grass tips and create entry points for infection
- Bag and discard clippings if disease is active to avoid spreading fungal material
- Water early in the morning only, giving grass time to dry during the day
- Limit watering during active infections to help slow fungal spread
- Improve drainage and manage nitrogen levels — excess nitrogen and poor drainage both increase risk
Know the High-Risk Window Late April through early fall is prime Brown Patch season in Middle Tennessee, as rising humidity in late spring creates the conditions this fungus needs to thrive.
Stay Protected with SecureLawn Since most fungicide treatments only last 21-28 days, consistent, well-timed applications are key to keeping Brown Patch from taking hold. Our preventative fungicide program is built around this timeline, with treatments scheduled through the highest-risk months to keep your lawn protected before symptoms ever appear.
Don’t wait until Brown Patch has already taken over. Prevention today means a healthier lawn tomorrow. Call SecureLawn at (615) 893-8455 or visit securelawn.com to get started.