A meat thermometer is another example of a tool superintendents use to monitor turfgrass growth. For optimum cool season turf growth (Bentgrass specifically) air temperatures need to be 50 degrees on the low end and about 70-75 degrees throughout the day. Grass starts to root when soil temperatures consistently stay in the 50-65 degree range (F). You can see above that our soil temperatures on greens are about 46*F. Once those temperatures hit the ideal range, the greens are going to be excellent!