The fastest grass seed to germinate is rye grass, which sprouts in five to 10 days. Fescue grass is next, germinating in seven to 15 days. Bermuda grass and bentgrass sprout in as little as 10 days. Centipede and buffalo grass germinate in two to four weeks, whereas bluegrass can take up to 30 days.
Check the grass seed label. The expected germination rate (the percentage of seeds that will sprout) is on the package. The best seed has a rate of 90 to 95 percent, but some types of grass seed will be closer to 80 percent.
Test the grass seed so you know type of germination to actually expect. Sow a sample area of grass seed in a pot or protected area. They will germinate a few days before the rest of the grass, because the soil is warmer.