We have received a number of calls, email, and electronic photos inquiring about brown patches to entire lawns turning brown apparently overnight (see photos). Following are the three most likely culprits:
• Seedheads – Especially on perennial ryegrass lawns, seed heads mowed by an even a marginally sharp blade will fray and turn brown as it dries out, generally within 24 hours (see accompanying Turf Tip). This is further enhanced by dry conditions (see #2). To overcome this condition, continue mowing regularly with a very sharp blade and water if the lawn is showing signs of drought stress.
• Drought stress in and around the hotspots next to sidewalks and drives- To overcome, simply irrigate thoroughly, preferably in the morning.
• Dollar spot-golf ball to soccer ball sized tan patches in an otherwise healthy green lawn. This is a disease that is most problematic under low nitrogen so an application of 0.75 to 1.0 lbs N/1000 sq ft should alleviate most of this problem (See accompanying Turf Tip).