As summer begins rolling into autumn, it’s time to get busy saving seeds from your summer harvest. Remember that HEAT and MOISTURE are the enemies to seed viability after storage. In other words, just the things that make a seed germinate when planted are the things that will kill them during storage and prevent germination later when planted. Even if the poorly stored seeds germinate, they may produce weak, spindly plants that do not produce fruit or vegetables. You may get carrot sprouts but never any root bigger than a thread even after months of growing.
When stored properly, some seeds can last 5-10 years, but this depends on the type of seed. Some seeds don’t do well the second year no matter how good the storage conditions. Seed banks use climate controlled environments (temp/humidity) to store their seed banks and grow them out every second or third year.
Fedco Seeds has a great chart on Seed Saving for Beginnners which gives great information including seed longevity. Most seeds store well for 2-3 years. Onion will only last one year and leek will last two at the most. Cucumbers, melons, and tomatoes can last up to ten years. I have successfully grown tomato plants from seven year-old seeds. Remember the younger the seeds, the more vigorous the plants will be.
If you are faced with an emergency where you had to get a garden in and survive off what you produce, you will also need to harvest seed from that garden so you don’t use up all your precious seed bank and have nothing left for the next season. If your emergency is such that you have enough time to grow a garden, you may need to do it for more than just one season. There is no substitute for experience in the garden.
I recommend a fantastic book by Steve Solomon called Gardening When it Counts: Growing Food In Hard Times. His premise is that you are gardening because you are going to live on what you grow so you cannot afford to waste money or to fail. This book was not written specifically for any particular state or zone and is not for the Square Foot Gardening crowd but it is full of extremely valuable advice gained from decades of experience with subsistence gardening. He also discusses seed longevity and seed saving.
In an ideal situation, you would be growing your seeds every year and saving seeds from the most vigorous plants and the best fruits. Watch for the plants that produce the biggest and best leaves and fruit. Tie a piece of yard around the stem, so you’ll remember those are the plants whose seeds you want to save.
By saving seeds from each harvest season, your seeds will always be fresh. Even if you live in an apartment, you can practice growing seeds on your balcony in pots. That said, you may purchase seeds for your garden and only plant some and save the rest for the next years. I do this. It’s a great money saver.
Seeds should be stored in an airtight container in a cool dry place. A mason jar in the refrigerator is ideal and easy. I store seeds from each type of plant in small, labeled paper envelopes. (These small packets make it very easy to trade seeds, too.) Adding a desiccant, oxy pack, or pumping down to vacuum would also improve shelf life. Do not store seeds in a frost free freezer without making sure the container is airtight. Ever seen an ice cube left too long in a frost free? It evaporates. This will kill your seeds. Seeds need to maintain a low level of moisture to survive, and if you’re packaging seeds yourself, that desiccant packet could make a huge difference in whether or not the seeds remain viable.
If you buy your seeds in a #10 can, keep it in the refrigerator. Every 10 degree F increase in temperature above standard conditions combined with a 1 percent increase in the moisture content of the seed, cuts the storage life of the seed in half.
Last but not least, make sure you purchase good quality seeds to begin with. Some seeds are nearly worn out when you get them. If you purchase seeds that have been stored in an outside nursery with the lovely trays of flowers under a mister system, they are in trouble. I was at a “big box” garden center the other day and the seed envelopes were under the shade cloth outside, in the heat, near the flowers. The packages had been so damp they were bent over. They had probably been out there all summer. I checked the envelopes and the seeds were loose in the packet and not inside a foil pack inside the envelope. At a “supercenter” I went to, the seeds were inside the air conditioned part of the store and well away from any moisture. These would be a much better bet. The best place to get seeds for storage is through mail order or order online from a reputable dealer. My favorite is Fedco Seeds for quality, price, and customer service. There are several other good ones as well. These seed dealers store their seeds appropriately and test germination each year for each lot.
Growing food is a big enough challenge but can you imagine trying to do that with old seeds that may or may not be viable? Take the time to not only learn how to save seeds but then store them so they will retain their optimal vitality.
Marta Waddell contributed to this article.