Find out if yours are still good to sow.
It's not unusual to find an extra packet of seeds in your shed when planting seasons rolls around—dusty and forgotten during last year's sowing. But how do you know if those seeds are worth planting this year? Do seeds have a shelf life? And if so, how long do they last above ground? We spoke with Jon Roethling, the director of Reynolda Gardens at Wake Forest University, to find out.
Shelf Life
As it turns out, most seeds have a shelf life of approximately one year. "After that time period, the percent of seeds that remain viable begins to decline," he says. That doesn't mean that you cannot plant seeds that have passed the one year mark, though. "Seeds that are two to five years old may still germinate, but at a reduced percentage." In short, the older the seeds are, the less likely they are to sprout in full—which may be a risk you are willing to take if you are doing a large planting, but something you may want to skip if you're short on time and space.
Seed Storage
If you want to keep extra seeds in good condition for the next planting season, Roethling suggests giving them the cold shoulder. "One of the best ways to store seed is in a refrigerator at cool, but not freezing, temperatures," he says. "Here at Reynolda Gardens, most of our seeds are stored in [reusable] containers in our refrigerator." For the absolute best results, you will need to make sure they are dry when you put them into storage, and that they remain dry until you are ready to put them in the ground.
Mystery Seeds
If you have found mystery seeds, or seeds of an unknown age, you may be wondering how you can tell if they are worth planting. According to Roethling, you can tell a lot about a seed by taking it out of the storage packet and having a good look. "Often, you can tell if a seed's viability has been impacted if it appears shriveled," he says. A shriveled seed may be a sign that the seed is old and dried out. If you suspect that your seed is getting close to the one-year mark, or is starting to shrivel, you may be able to stretch its timeline with some care. "Seeds that may be at the tail end of their shelf life may benefit from a soaking unless they are thin, papery seeds, such as lilies," he says.