As temperatures drop in fall or winter, turf grasses go dormant, turning brown and using their energy to maintain their root systems throughout the colder months. When temperatures rise again in spring, these grasses begin greening up at various temperatures, depending on the grass type.
Cool-season grasses, such as blue grass and tall fescue, begin growing when temperatures reach at least 40 degrees F and grow best between 60 and 70 degrees F, according to the North Carolina Cooperative Extension. The roots of these grasses grow at soil temperatures of just 33 degrees F. Cool-season grasses in regions with mild winter weather may not enter dormancy at all.
Warm-season turf grasses include zoysia, St. Augustine and Bermuda grass. These grasses go dormant following the first heavy frost in the fall and remain dormant until temperatures rise to at least 70 degrees F; they prefer temperatures of 80 to 95 degrees F. Soil temperatures must reach at least 64 degrees F for warm-season grass roots to grow, according to North Carolina Cooperative Extension.
Warm-season grasses damaged by very cold temperatures or long periods of cold may fail to green up well in the spring. Spring fertilization, along with proper watering and mowing for your specific grass species help encourage healthy turf growth and color. Increasing daylight hours also encourages spring turf growth.