The basic germination times vary based on variety and the time of year. Cool-season grasses tend to germinate quickly, usually between three and 14 days. Perennial rye grass (Lolium perenne), which thrives in U.S. Department of Agriculture plant hardiness zones 3 through 8, can germinate in as few as five days, although it can take up to 10 days, for example. Warm-season varieties might take longer, anywhere from five to 30 days. The hardy zoysia grass (Zoysia), for instance, grows in USDA zones 6 through 9 and can take 10 to 21 days to germinate.