Woofie,
That's the same site I was going to recommend. I'll look for a few more links.
I agree that most seeds can be frozen
once they are very dry. That also kills many insect eggs, I'm told.
I often find the claim that for every 10% drier, or 10 degrees F colder, you "double" the viable lifetime in storage. However, below 15% relative humidity, you might start to kill some seeds.
That's why I stopped keeping a big paper coin envelope of silica gel in my sealed jars and tubs. Now I usually have a smaller envelope of gel, not TOO fresh, and take it out if that jar isn't going to be opened and closed every few weeks or months. I don't want them to get TOO dry. You can buy a pound or two of silica gel in any craft store - used for drying flowers. You can regenerate it by baking a thin layer for 3-4 hours at 250F. (Overheating, like above 280 F, can damage the gel so it doesn't absorb as much humidity.)
I think that silica gel is overkill if you only need seeds to last 3-5 years. If losing a little germination rate or vigor is not a huge deal, any reasonably dry, dark, cool spot is OK. Temperature SWINGS and humidity SWINGS are bad.
Dry rice or macaroni, baked almost-brown are milder desiccants.
Just get it really dry
before you seal seeds in anything impermeable. If there is doubt about how dry the seed is, leave it in paper. (Coin envelopes or business envelopes saved from bills, or fancy-folded from a sheet of paper).
1. "triple foil packets with heat-seal" - suitable for world-class seed vaults and collectors of rarities. The kind of people who also have deep freezers or even liquid nitrogen.
2. Sealable jars: metal screw-lid glass jars (Mason jars, jelly and jam jars) 100%
3. Seal-a-meal pouches - 98% or 99% ideal
4. plastic jars with screw lids: not quite as tightly sealed but OK to prevent swings in humidity. This is what I use, but I'm looking for some cheap gaskets or soft rings.
If saving common seed for 3-5 years, not trying to preserve something rare and irreplaceable for 10-15 years,
all the above are overkill.
5. Plastic freezer bag with Ziploc - fine for normal seed savers, in the fridge or the freezer or a cool basement.
6. regular plastic baggie with Ziploc - OK if you don't have lots of humidity and humidity swings. (I use these inside my big plastic tubs, just to keep each variety separate, and, for fussiness, "double-bagged".
7. paper envelopes and/or paper bags - the most common means of storing crop seeds. This works fine for a great many people, for 3-5 years.
http://www.kew.org/science-res......
- - - - Woofie's link has since then redirected to some spammy site - - - -
http://howtosaveseeds.com/stor...
http://www.seedcontainers.net/...
http://www.ehow.com/how_557896...
http://www.underwoodgardens.co...
http://www.southernexposure.co...
technical paper:
http://www.seedcontainers.net/...
