Great idea!!

Thank you! For a little while, I kept silica gel or "Drierite" in an open plastic envelope inside the jar. It tended to tip over, which was messy!

Now I like keeping the silica gel in a paper coin envelope, but you could also use half of a letter-sized envelope taped and maybe stapled closed.

I really like the "humidity cards" you can buy from ULINE or Driorite. They let you know when the desiccant is exhausted, or that you put in so much that the humidity goes below 20%.

You can fit a lot of 2x3" Ziplocs into one 3-pound peanut jar. Usually, within the jar, my 2x3 Ziplocs are grouped into 3x5 glassine envelopes, or bigger Ziplocs up to sandwich-bag size. Those fill up a 3-pound tub pretty fast.

https://secure.drierite.com/ca...

I think it is important to keep the tightly-sealed jar size fairly small. Otherwise, every time you open it to take out one packet, you let in a large volume of humid air that exhausts the desiccant rather quickly.

Well, I learn something new all the time on here.
Thanks so much for the information.

I stumbed onto the "baked rice dessicant" tip while looking up how to regenerate silica gel by baking it at 250 F for several hours (but no hotter).

I tried to find out the best temp for over-drying rice, but all they said was "until it's not-quite-brown".

Someone sent me some fresh seeds they hadn't quite finished drying yet - in a Ziplok along with dry rice grains in the Ziploc! The seeds were much smaller than rice grains, hence easy to separate.

I used to worry about OVER-drying seeds, but the humidty cards suggest that isn't a problem when I use only a small pkt of silica gel (1-2 tablespoons). Usually I open and close the jar a few times while setitng it up, and the seeds themselves are in Ziplocs that slow down the rate at which they lose humidity, even if the air in the jar itself is "too dry".

Plus, I have paper labels inside each Ziploc, and paper absorbs humidity and then releases it gradually. So I figure that acts as a "buffer" for the seeds.

Whenever I check a pkt, the paper is not "cracking-dry", so I figure the seeds are OK. And they do sprout for me, so I haven't killed them with too much dryness.

What I read suggests that seeds last longest when the humidity and temperature are both low and STEADY. Fluctuations, not so good. For a while I was packing 2x3" Ziplocks inside bigger Ziplocs, so there two barriers to moisture movement. But now I think that is overkill. Glassine envelopes take up less room, when I wnat to group together 10-20 Ziplocs by variety or genus.

Wow! Lots of great info here! Thanks for directing me to this blog Rick! Maybe I need to stop throwing seeds away (when I have too many).

You're very kind! I've been looking around and asking around, and I read a lot of seed vendors saying "your seeds will only last 2-3 years and you have to buy more all the time!"

Then I ASK around, and experienced gardeners say things like "at least 5 years", or "I found a bag of seeds in the shed or garage, completely unprotected, and got decent germination after 10 or more years"!

Sure, not every species lasts forever, but a lot of published lists are WAY too pessimistic.
Or they consider germination rates lower than 85% unacceptable.
Or they want the seed to germinate reliably under THE MOST unfavorable conditions imaginable.
Or they just want you to throw away seeds every year, and never trade or save your own!!

Maybe many seeds lose some vigor every year, and experienced gardeners pamper their seeds, so that even a tired old seed can get its head above ground.

But please don't throw seeds away if they still have a date on the packet! Trade or contribute them to someone and just mention their age. A lot of "trade" packets have been circulating long enough that the envelopes are pretty beaten up, but still germinate!

There was some immature fruit tissue frozen in tundra back in the Upper Pleistocene, and some lab coaxed it to germinate and grow to maturity over 30,000 years later!

http://blogs.discovermagazine....
(Google 30 000 year old flower)

YMMV!

An earlier project germinated and grew a 1,300-year-old lotus seed from northern China.

Another group germinated a 2,000-year-old palm date seed from Israel in 2005.