Thermal convection and frost on zoysia

View Larger

Photo submitted by Dr. Fred Yelverton, NC State University (@FredYelverton on Twitter), December, 2020. The pattern frost on zoysia matches the pattern of zoysia dormancy illustrated in this photo.  The frost and dormancy patterns are caused by porous convection. In short, warm air from the soil moves up the plants like a chimney and cold air flows down nearby inducing dormancy next to green grass. Mowing height controls the spacing between the green mottled areas. Lower mowed grass is unable to develop a significant amount of thermal convection and therefore remains uniform in entering dormancy. The appearance is similar to that observed in kikuyugrass and bermudagrass.

---