Unopened grass seed may last longer than an opened bag, but how you store them makes a difference in how long the seeds will remain viable.
Most grass seed I'm familiar with has a viability around 85% – meaning that if you. time, but seeds that are stored in a cool, dry place should last a long time.
This is how long it will take to actually see the grass growing. Until this point, the seed, or the soil and mulch in contact with the seed, must stay moist. It doesn't .
Do you expect every grass seed to grow? How long until grass first appears? Will old seed still sprout?. The success of your lawn project is not completely under your control, but you can do a lot to improve the final result. Seed germination is .