I live off-grid so have limited freezer space. What I do is ensure the seeds are well dried, then put in envelopes- label well and then put them in a airtight plastic black box in the basement where the temperature is not always constant but the most stable climate I have.
It's not as good as a freezer, but most things seem to keep for 3-4 years, after that things get patchy.
Alan Whitaker wrote:I've always stored my seed in a freezer. I have a 10 Cu.Ft. freezer full of seed right now. But I would like to get away from having to rely on electricity. I'm in NE TX where it is hot and humid during the summer and wet in the winter. I've tried storing seed without the freezer before, but after a couple of years, the seed usually won't germinate. I have onion seed that I've stored in the freezer for 9 years that still has decent germination rates. Anyhow, how would one store garden seed in this climate (hot, humid) without the use of electricity? I want to store for years, not year to year. Sometimes, I just can't get it all planted and I like to grow out different varieties and save seed, so I'm usually just growing one variety of each. So what is the latest and best way to do this?
maintaining dry seeds in a steady, cool temperature is one of the best ways to maintain viability, in my experience. For most types of seeds, refrigeration or freezing is not necessary to enable good germination rates for 3+ years. Fully dehydrated dessicant packs (rechargable) added to seeds containers can help with humidity if the containers are sealed well. Vacuum sealing is another option to maintain viability. The manual "pump-n-seal" system is an option if you don't have electricity available, or would like to prepare for it's loss. To maintain cool temps without electricity in your climate, perhaps a buried, insulated box would work, if you don't have access to a full sized root cellar.
An option for seeds like onions, which often have a short shelf-life, growing out some each year is probably the best way to maintain the line. If you don't have the space on your property to allow for a good separation between varieties of the same species, isolation screens which can be placed over the patch going to seed can be fashioned pretty easily.
The colour usually shown by silica gel is due to an indicator, added to see directly when it is dehydrated and when it has absorbed moisture. For many years, cobalt chloride (Cl2Co) has been used. This substance gives the dehydrated gel a strong blue colour and a pale pink colour to the gel having absorbed moisture. Recently, the European Union banned its use because of considering it carcinogen through inhalation. A search for new alternatives led to some iron salts, where the change in colour can be poorly distinguished. At present, the most advisable alternative is methyl violet, which gives the dehydrated gel an orange colour and a green colour to the hydrated gel.
So, those little packets you find in camera and electronics boxes, as well as 90%+ of what is sold retail is NOT suitable for food seeds.
P.S. The site listed in the quote has an excellent article on long term storage of seeds. They are doing it for decades.
I've used canning jars. Picked up a couple hundred of them at a church flea market for 10¢ each, another couple hundred on craiglslist for 3 bucks/dozen. They take up more space than the ziplock bags. I've gotten bugs in the bags, never had a bug in the jars unless they came out of the seed.
Seeds that I have larger quantities of, like brassicas and favas, I just keep on top of the bookcases in the living room. If I have saved a lot of seed, I don't care about germination rate . I did find bugs in one paper bag this year (10-15 years old), so I will be more consistent about putting them in containers now.
I also don't clean my seeds, necessarily. For some varieties (brassicas, again, are an example) it just doesn't seem worth the trouble. I save whole stalks/pods, and crumble them into the bed. Or, if only starting a few in trays, I separate out the seeds at time of planting. A side benefit is that the chaff makes it easy to see where I have planted.
Second, some vegetables will self-seed but they might also cross with wild relatives and produce less nice offspring, but other times offspring will be just as good and spread in the garden. This can happen with radish for example, and several flowers. No need to worry with seed in those cases.
Third, some common seeds lose viability rapidly: onions especially, parsnips and scorzonera, some basils: even after 1 year you might find your entire package does not germinate at all.
But in general tomatoes, peppers, brassicas, squash keep good and in some of my cases they have even last 6 years. They might lose viability a bit, but still germinate. Sometimes one variety out of several fails to germinate after 5 or 6 years. I kept these seeds just in a drawer inside the original package, inside a plastic bag, without thinking too much. Sometimes I forget them in a room with sunlight, I know that is not good. Humidity is also bad.
Long stored seeds might take longer to germinate.
Beans: these you should save in a glass container because otherwise some insects will like to eat those over time!
Carrots: they have lasted 4 years well. I have had one package of lettuce losing viability after some years.
If you have a rare variety the best is to grow it, save seed (taking care of not crossing with other varieties - this happens easily with brassicas for example) and then save a lot of seed for yourself, give some to friends, and keep growing that variety.
Also, I've had pretty good luck with storing plants IN my compost pile over winter. It's obviously mostly finished (cool) compost that will be used the following spring. It stays just above freezing in the center though the winter. I take out kale, collards, chives and some other plants, root and all and just throw them (gently) into the middle of the pile before the really cold weather hits. Surprisingly, many of them make it through to spring. When I use the compost in the spring garden prep, I just take the plants and put them in an empty spot in the garden. This year the collards went right to seed but due to the huge root mass from last years growth, they produced a bucket of seed. I'll be planting that seed next year or maybe later this summer for a small fall harvest.
I wonder.. what other plants this might work for?