Warm season grasses are in their active growth phase in the warmer starters, starting in late spring and going dormant in early to mid-fall, usually after the first frost. Warm-season varieties prefer full sun, heat, and do well in dry conditions. Cool season grasses are in active growth longer, starting in early spring when it is still cool and not going dormant until late fall. Cool season varieties prefer cooler temperatures, shade and do well in humid conditions. Cool season grasses will maintain a green look even while dormant, whereas warm season grasses tend to turn a brown color. Finally, warm season grasses tend to use 30 to 50 percent less water compared to cool season grasses.