by Jill Henderson – Show Me Oz –
Seeds are living, breathing, life forms capable of remaining dormant for long periods of time, germinating only when environmental conditions are just right for the growth of the plant they will soon become. But even the best kept seeds don’t last forever. If you save your own flower, vegetable or herb seeds, you can help increase their lifespan by following just a few simple steps. In this week’s Show Me Oz, we’ll talk about the right way to dry and store your seeds and how long you can expect them to live.
Drying Seeds So They Last
One of the most important aspects of preserving the health and vigor of dormant seeds is the way they are dried. It takes a lot of time and energy to raise a crop to the point where it produces seed. Sometimes it’s as easy as waiting for the squash or watermelon to reach eating stage, but some plants need two full seasons before it will reproduce. And once you’ve gone to lengths to see your seed come true, it is so important to take the time to dry your seeds correctly. Seeds that are properly and carefully dried will last longer in storage and germinate better when planted.
Seeds that are not dried and stored properly will not achieve a deep state of dormancy, which means they will spend much energy exchanging oxygen for carbon dioxide, also known as respiration. It’s the most important thing seeds do to stay alive, but respiration takes energy. If seeds spend too much time breathing, they exhaust the energy needed later on to germinate and sustain the early growth of the plant.
Most seeds dried at room-temperature will have a moisture content of 10%-20%. At these levels, seeds that are packaged in glass or plastic can rot, mold or germinate; at the very least, seeds with a high moisture content will rapidly decrease in rate of germination.
The only seeds that dry well enough to be frozen without special treatment are tiny, hard seeds like eggplant. Room dried seeds should only be wrapped in acid-free paper packets, which can then be grouped into a large rigid box and stored in a dark area that remains below 50° F. Stored this way, most seeds should maintain at least 50% germination rates for several years.
The ideal moisture content for most seeds in storage is between 6-8%, at which point seeds can safely be packaged in airtight jars or plastic before being stored or frozen. Seeds should never be dried in the oven, dehydrator, microwave, or in direct sun, as high temperatures can kill the embryo within the seed.
The safest, easiest way to achieve satisfactory drying is through the use of silica. Once seeds have been room-dried, they are wrapped in paper packets and placed on top of an equal amount of silica that has been spread in the bottom of an air tight container. The seed packets are left in the container for 2-3 days before being removed.
After drying the packets may be enclosed in airtight jars or plastic bags and frozen or kept in the refrigerator. Do not store seeds in, or with, silica as it will absorb all of the moisture from the seeds and kill them. If seeds are kept in the refrigerator or freezer, take special care to allow all containers to come to room temperature before opening. When a very cold container is brought into room temperature, condensation forms on the outside. If the container is opened when cold, the condensation will also form on the inside, potentially rehydrating the seeds within.
Storage Times for Common Vegetable Seeds
Once your seeds have been harvested, dried and stored, it is important to remember that they are living things and their life spans are finite. In other words, they won’t remain viable forever. In perfect storage conditions seeds will last anywhere from one to six years.
If storage conditions are average to poor, germination rates could possibly be reduced by as much as 50% – that means that up to one-half of all saved seeds could fail to germinate after being planted. That’s a lot of seeds to lose if you are depending on a crop. The following table of storage times is a helpful guide for storage lengths of some common food crops. Some crops are listed in more than one group either because of differences in species or cultivars, or in the natural variances in factors that determine seed viability.
Short (1-2 years): Anise, caraway, chive, cumin, leek, lovage, marjoram, onion, oregano, parsnip, peanut, salsify, sweet cicely.
Moderate (3-4 years): Beans (most common types), broccoli, carrot, celery, celtuce, chervil, corn, eggplant, fennel, ground cherry, leek, lettuce, parsley, parsley root, peas, pepino (melon pear), peppers, potato, tomatillo, tomatoes.
Intermediate (4-5 years): Asparagus, basil, dill, okra and Brassicas such as, broccoli, broccoli raab, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, Chinese mustard, collards, garden cress, kale, kohlrabi, leaf mustard, mustard greens, radish, rocket, turnip and rutabaga.
Long (6 + years): Artichoke, beans (Vicia and Vigna generas), beets, cardoon, celeriac, celery, chicory, cucumber (common, burr, Indian gherkin), endive, gourds, melons, orach, quinoa, spinach, squash, sunflower, Swiss chard.
If you’re interested in learning to save your own seed, check out these other great articles about seed saving on Show Me Oz:
© 2014 Jill Henderson Feel free to share with a link back to the original article.
Save money, become more self-sufficient and avoid GMO’s by saving seeds! This excellent resource for beginning and hobby seed savers takes you step-by-step through every aspect of saving your own seed in plain English.
Jill Henderson is an artist, author, and the editor of Show Me Oz . Her books, The Healing Power of Kitchen Herbs, The Garden Seed Saving Guide and A Journey of Seasons can be found in the Show Me Oz Bookstore. Jill is a contributing author for Acres USA and Llewellyn’s Herbal Almanac and her work has appeared in The Permaculture Activist and The Essential Herbal.