Cool season grasses describes a group of grass species that grow best during the cooler times of the year. These grass species have a longer growing season as compared to the warm season grasses. The cool season grasses green up earlier in the spring which is determined by the ambient (air) temperature when these species begin to actively grow and require care. Adversely, consistent soil temperatures dictate when new seedlings will break dormancy and begin to germinate.
The cool season grass species will have the highest forage productivity in the spring followed by fall. The summer heat stress will slow the growth of these plants as they are protecting themselves for survival. As you will see below. Some cool season species will perform better under lower moisture conditions than others as they have deeper root systems, allowing them to reach deeper for moisture to survive.