Storing saved seeds
Many garden seeds can be collected now and stored for planting in spring. Echinacea seeds are drying on their seed heads –– at least those that the goldfinches aren’t eating. ‘Jimmy Nardello’ sweet peppers are long and red; it’s time to eat the flesh and save the scraped-away seeds. ‘Chateau Rose’ tomato seeds are ripe for the taking (i.e., for the fermenting).
How long can seeds last in storage? There are tales of 3,000-year-old lotus seeds from Japan, and of 3,000-year-old barley seeds coming from King Tut’s tomb, but plant physiologists say those are likely just tales –– that the artifacts found with the seeds were dated but the seeds weren’t, and/or that the found seeds weren’t viable (capable of germinating).
Viable 600-year-old seeds of Canna compacta have been found, say Lincoln Taiz and Eduardo Zeiger in the textbook "Plant Physiology." “The Canna seeds had apparently been inserted into the immature seeds of a growing walnut fruit before the hard outer shell formed,” they write. “Once the shell hardened and the nut dried out, the result was a rattle. Native people strung the rattles together to form a necklace. In this case, the seeds had to be at least as old as the walnut shell, and carbon dating of the shell indicated that it was about 600 years old.”
Most of us gardeners aren’t worried about saving our seed for 600 years –– which is good, because most garden seeds are viable for one to six years. The website of Hill Gardens of Maine, hillgardens.com/seed_longevity.htm, has an extensive list of vegetable and flower seeds and their longevity – under good storage, which means cool conditions and uniformly low humidity. Okra (one to two years) and parsnips (one to three years) are on the low end of the longevity (shortevity?) spectrum; cantaloupe seeds may last six to 10 years; other vegetable crops are in between. I’m harvesting pepper seeds this week, as the Jimmy Nardellos turn red (seeds should come from ripe plants). According to Hill Gardens, pepper seeds last three to five years, stored properly.
As a group, flower seeds tend to be shorter lived, with many lasting only one to three years. Seeds of most popular herbs, says Hill Gardens, won’t last more than about a year.
To harvest seeds from open-pollinated, non-hybrid tomatoes, I cut the fruits into quarters or more (depending on the size of the fruit) and put the cut pieces in a glass of water. After four or five days, the viable seeds have fallen to the bottom of the glass and the pulp and nonviable seeds have floated to the top. This is a slightly messy process, much loved by fruit flies, but worth the minor effort.
On day five or when numerous seeds have settled to the bottom of the glass, just decant off the top portion of pulp and water (into the compost pile) and add clean water to the glass. Let the seeds settle again and pour off most of the water. Repeat this process two or three times until the water runs clear. Then pour the remaining water and seeds through a tea strainer, plop the seeds from the strainer onto a few sheets of newspaper, spread them out and let them dry.
Once seeds are dry, wait for a day when the humidity is low and then put the seeds in small Ziploc bags, seal them tightly, and place them in a cool, dry place. The bag should seal out most moisture.
You can also store seeds in paper envelopes placed in a Mason jar on a dry day, perhaps with some desiccant such as silica packs or a packet of dried milk in the bottom of the jar to absorb moisture. Seal the jar tightly and place it in a cool cellar or refrigerator and wait for spring.