The time for preventative fungicide applications for fairy ring control will be approaching over the next couple of weeks. Based on our field research, two applications of a DMI fungicide beginning when soil temperatures reach a 5 day average of 55° F provides excellent control.
If you would like to monitor soil temperatures on your own, you can do so using the NC State Climate Office Advanced Map. For sandy soils or sand-based putting greens, the average daily soil temperature will be very close to the average daily air temperature, so you don't necessarily need a website or fancy weather station. Just take the average of today's high and low temperature, and when that number is at or above 55°F for 5 straight days, it's time to pull the trigger!
For more information about fairy ring, including control recommendations, click here.