Grass growth generally stops when temperatures fall to 50-55 degrees Fahrenheit or below. However, other factors such as the type of grass, soil temperature, and climate can also affect when grass stops growing. For example, cool-season grasses such as Kentucky bluegrass, ryegrasses, bentgrasses, and fescues can still flourish comfortably in temperatures below 50 degrees Fahrenheit but gradually stop sprouting as it approaches 32 degrees. Warm-season grasses, on the other hand, thrive between 80 and 95 degrees Fahrenheit and will stop growing when soil temperatures drop below 55°F. Its important to research the type of grass you have to know when it could potentially stop growing.