grass seed will maintain good germination over time if stored properly. Germination will go down over time, but storage condition is critical. Also letting the bag of seed sit in the sun or hot car or truck will kill the seed very quickly. Remember, even if germination is 50% you can usually get a good stand because most people over plant. It only takes a few hours in an oven (hot car or truck) to kill the seed. If it hasnt sprouted by now it wont.