Nearly every gardener has at least one. It could be a whole drawer, a small box, or maybe plastic bin brimming with mystery seeds. How old were these again? Are they still good? Now, what was this one?
Despite our best efforts, it’s easy to end up with an out-of-control seed collection. Fortunately, Kathryn Gilbery recently shared some of the most common seed storage mistakes people make—and tips for avoiding them.
And she should know. Gilbery serves as the Exchange and Outreach Coordinator for Seed Savers Exchange.
1) Storing seed too soon
“Seeds need to be properly dried before they go into storage,” Gilbery says. “If they aren’t dry enough, then they’re at risk for mold or other fungus issues.”
Even seeds in unopened, paper packets can take on moisture in humid climates. Whether you’re inspecting mail-ordered seed or you’ve scored seeds from a neighbor, use the “fingernail test” to assess dryness. “Poke [a seed] with your fingernail and, if it squishes or leaves a dent, then it’s not dry enough,” Gilbery explains.
If need be, spread seeds out on a screen to dry. You can speed this process with a box fan. Just don’t overdo it!
2) Keeping seed that is too dry
Not sure whether seeds are too dry? You can go beyond the fingernail test to find out.
Pinch the seed between your fingers. Seeds that crush very easily have likely lost too much moisture. And, unfortunately, Gilbery notes, “There isn’t really a way to reclaim a seed that has been over-dried.”
3) Allowing weevils, mice & other pests access to your seeds
Assorted creatures easily chew through paper bags, envelopes or even cloth sacks to get to the delicious seeds inside. Small glass jars or plastic bottles are preferable, since these help keep pests out.
They’re also more airtight and can help keep moisture at bay. “If you’re really interested in long-term preservation, one of the best practices is storing seeds in something less permeable [than paper],” Gilbery adds.
4) Failing to use cold storage when warranted
“If it’s seed that you’re just going to be planting within a couple months or a year, then it’s going to be just fine at room temperature,” she says. “But, if you want those seeds backed up for the future, then refrigerating or freezing is an option.”
Cold temperatures can extend seed longevity by many years. Just be sure to dry seeds thoroughly and place in an airtight, glass or plastic container ahead of cold storage.
And when it’s finally time to take these seeds out?
“When you take something out of a cold place and bring it to a warmer place, it’s going to condense,” Gilbery says. “So, when we take seeds out of the freezer here, we leave them on the counter for about four hours. That’s so none of the condensation can get inside of the package.”
5) Storing seeds in bright sunlight
Dry, dark places—think closets and cupboards—are best for long-term seed viability.
6) Exposing seeds to too much temperature fluctuation
Bursts of air conditioning and the heat from a sunny window can be enough to affect stored seeds’ germination rates. “You want to find the most stable temperature in your house,” Gilbery says. “That might be a basement or a closet—something that has remains steady.”
7) Seeds are poorly labeled—or not labeled at all
After emptying store-bought seeds into an airtight bottle, be sure to save the original seed packet. “You can put the packet inside the jar,” Gilbery suggests. “There’s lots of good information on that seed packet, so they’re always good to keep around.”
Next, add a sticky label to the outside of the bottle. At Seed Savers, Gilbery says, “We always label the outside of the container, but we also put a label on the inside of the container for our larger seed storage. That way, if the outside label was to fall off, then you’d still have the label on the inside.”
Even if you’ve kept your seeds in less-than-ideal conditions, Gilbery says, “It’s helpful to remember that seeds really want to grow—they want to live and thrive. So, go ahead and try planting them. People are usually surprised at what grows.”
For more on seed storage and saving your very own seed, check out The Seed Garden: The Art & Practice of Seed Saving. Over time and with practice, you’ll get better at making important observations about your plants’ growing conditions and the seeds they produce.
You’ll get better at harvesting, processing and, yes, storing this seed, too.