A picture can say it best sometimes, as is the case this time.
Courtesy: Kristen MacMillan, Agronomist in Residence, University of Manitoba
Warm and sunny means above 25 C.
Yellow triangles mean use caution and always check to see how much breakage you’re causing after rolling only a small patch before deciding to continue.
Green check marks indicate rolling shouldn’t cause damage if done under proper conditions.
Red X = don’t roll at this stage!