How Long Does Grass Seed Stay Viable?

Question: How Long Does Grass Seed Stay Viable?

Readers, Skip and Wanda write, "The snow and flooding have left a huge section of the lawn with no grass. Can grass seed be planted now or should we wait until the fall? If we can plant now, can we use the old seed that should have been used in the fall?


What type of grass do you have? While many prefer to start new lawns composed of cool-season grasses in the fall, they can be started in spring, too (as can lawns composed of warm-season grasses).

In terms of type of seed, the same type that you'd use in fall can be used in spring. But I think you may be asking, How long does grass seed stay viable? The answer varies according to the grass seed and the conditions, but a bag of old grass seed won't go as far as a bag of new grass seed. I've heard that each year grass seed sits around, you'll lose up to 10% germination.

So the question becomes one of how to use old grass seed most effectively. To be safe, I would buy a small amount of new grass seed to mix with the old grass seed. When you sow the grass seed with your lawn spreader, use a slightly higher setting (so that you're releasing a slightly greater amount of grass seed than is called for).