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Vanisle_BC
- Greener Thumb
- Posts: 1356
- Joined: Mon Apr 13, 2015 9:02 pm
- Location: Port Alberni, B.C. Canada, Zone 7 (+?)
Freezing seed
Does freezing seed extend its life indefinitely?
As far as I know it does extend the life of the seeds if it is properly stored, but I think the germination would still be affected over time. I know 50 year cryogenically frozen seeds have been germinated, but I also heard that seed banks plant out stored seed periodically to get fresh seed to store. The type and condition of the seeds would need to be taken into account.
The extension agent said that he was able to plant out 25 year old seeds that were stored cryogenically in the seed lab.
The extension agent said that he was able to plant out 25 year old seeds that were stored cryogenically in the seed lab.
The major word in this discussion is "cryogenic" the other part is in a seed lab. Special care must be taken during the freezing process. If we just put seeds in a freezer the risk is that any moisture inside the seed casing will crystallize and burst thus rendering the seed useless for germination.
Seeds kept in refrigeration or even in air tight containers in cool places will germinate after many years, some up ten or twelve. Germination percentage decreases over time. Some of the seed banks that freeze seeds can keep them for many years. But for us home gardeners there are seed sources that keeping seeds frozen for long periods of time is not practical.
Seeds kept in refrigeration or even in air tight containers in cool places will germinate after many years, some up ten or twelve. Germination percentage decreases over time. Some of the seed banks that freeze seeds can keep them for many years. But for us home gardeners there are seed sources that keeping seeds frozen for long periods of time is not practical.
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Vanisle_BC
- Greener Thumb
- Posts: 1356
- Joined: Mon Apr 13, 2015 9:02 pm
- Location: Port Alberni, B.C. Canada, Zone 7 (+?)
Thanks and yes I'm familiar with the word cryogenic; even since way before I read any Arthur C. Clarke 
. I note the need for drying before freezing. I'm not sure how well I can accomplish that but post-freeze germination testing would tell. An interesting experiment for my 'lab' (kitchen). And my little greenhouse is a pretty effective place to dry without burning.
I regularly keep all my seeds in the fridge, as dry as I can, and they stay viable longer than 'normal'; although I try to use them within their 'official' life span. But in this case I'm saving parsnip seed which does not 'germinate after many years'. Neither do onions, assorted alliums (allia!) and doubtless some others (corn? I don't grow that so haven't paid attention.)
One parsnip head gives a TON (not literally) of seed! I don't really need to save it indefinitely but I hate to throw most of it away and repeat the overwintering of the mighty plant & root if I want to keep saving seed.
I harvested the seed today - dried 'on the vine' and I'm already testing it.
. I note the need for drying before freezing. I'm not sure how well I can accomplish that but post-freeze germination testing would tell. An interesting experiment for my 'lab' (kitchen). And my little greenhouse is a pretty effective place to dry without burning.I regularly keep all my seeds in the fridge, as dry as I can, and they stay viable longer than 'normal'; although I try to use them within their 'official' life span. But in this case I'm saving parsnip seed which does not 'germinate after many years'. Neither do onions, assorted alliums (allia!) and doubtless some others (corn? I don't grow that so haven't paid attention.)
One parsnip head gives a TON (not literally) of seed! I don't really need to save it indefinitely but I hate to throw most of it away and repeat the overwintering of the mighty plant & root if I want to keep saving seed.
I harvested the seed today - dried 'on the vine' and I'm already testing it.
Keeping seeds cold and dry even in a refrigerator does prolong seed life. But different seeds have different viability. Tropical seeds notoriously have short viability and many tropical seeds cannot be stored at all. Most seed kept in refrigeration, and especially sealed in foil packets, have lasted the longest. Still most seeds average life span is 3-5 years. Corn is 2 years, beans and dill can last 9-12 years, but germination rates will decline every year.
In my climate it is hard to dry seeds because of the high humidity. Some seeds I store with powdered milk as a dessicant. They still usually don't last as long as commercial seeds. However, really fresh papaya seeds have a really high germination rate, much better than seeds I buy from the store and cheaper too considering the number of seeds in a papaya. Local papaya are not heat treated so they germinate well and it is not hard to get a good papaya from somebody.
I think I read that seed labs do progressive cooling before finally storing them in liquid nitrogen.
In my climate it is hard to dry seeds because of the high humidity. Some seeds I store with powdered milk as a dessicant. They still usually don't last as long as commercial seeds. However, really fresh papaya seeds have a really high germination rate, much better than seeds I buy from the store and cheaper too considering the number of seeds in a papaya. Local papaya are not heat treated so they germinate well and it is not hard to get a good papaya from somebody.
I think I read that seed labs do progressive cooling before finally storing them in liquid nitrogen.