>> seeds for my Butterfly Pea vine. The seeds got moldy so I had to dump them. I've still got seeds from that plant in an envelope

Lin, I agree with you. That is super important. Any seed has to be really dry (fully air-dry no matter how long it takes) before you seal it inside plastic - even if the plastic "breathes". Like you, I use paper envelopes to let them dry for weeks or even longer.

Folding the flap down and securing it with a paper clips keeps them from falling out if the cat knocks them over. And I can write the name and date on the envelope. I save return envelopes from bills that I get in the mail. You can let entire blooms continue drying inside some big envelopes.

Usually I print labels on the laser-printer at work to get fine print that isn't blurry and won't run when damp. Then I put the label inside the Ziploc (or pill bottle) so the Scotch tape can't fall off or be pulled off. It makes it easy to transfer the seeds AND the label from one container to another: I just pour the label in along with the seeds.

>> saving those little silica pouches that come in vitamins etc. that keep the pills dry ... they will also keep the seeds dry.

Unfortunately, a small amount of silica gel such as those pouches contain will only absorb a small amount of humidity before it becomes saturated and loses its power to keep things dry.

Silica gel can be regenerated by 2-4 hours at 250F, but I'm betting that will melt and/or scorch the pouch or the pellet.

I bought a pound and a half of silica gel from a craft stroe (flower-drying isle). Maybe $6-7. I staple a tablespoonful into paper coin envelopes, but you could roll and fold some paper around a smaller amount and fit that into a pill bottle. Kept very tightly sealed, a pound of silica gel would probably be enough for thousands of pill bottles, so you could replace them every few months if you needed to.

I put small seed packets (2x3" Ziplocs) into large plastic tubs (I think they held 2 pounds of peanuts or a similar amount of peanut butter. Then I drop the Ziplocs with seeds and one coin envelope with silica gel into each big plastic tub. Every time I open a tub, humid air rushes in, so the silica gel packets only last 4-12 months.

Also, if I use too much fresh silica gel and don't open the tub for a month, it gets down below 10% relative humidity, which is dryer than is really good for seeds.

Great information Rick ... thanks so much for sharing!

I went crazy with silica gel at first, but I think I got my sees TOO dry some of the time. Now I use smaller pkts and don't change them until the RH gets up to 20%

The little humidity-indicating cards are pretty handy, but ULINE only sems to sell 400 / $35 as their minimum order (18 cents each).
http://www.uline.com/Product/D...

These from Drierite can be bought as onsies or twosies for 40 cents each:
https://secure.drierite.com/ca...

Less potent desiccants are easy to find.

You can bake rice or macaroni at low heat until just before it turns brown. That gets them extra-dry.

But now you have to seal them tightly, quickly, before they adsorb humidity and lose their value. But you can't put them into plastic hot or it will melt. So pour them into some glass jar with a tight lid. As it cools, you will pull a vacuum, so crack the lid a few times as it cools to keep from building so much vaccum that you can't get it open.

Then put some extra-dry rice or macaroni into the bottom of each pill bottle to suck up any humidity that the seeds release, and what diffuses in past the (not-very-tight) seal each pill bottle has with its lid.

To keep the seeds separate from the rice, i hope you can figure out something practical! Folding one or both up in a small paper envelope seems like a necessity.

Or put all your pill bottles into one big tub or really-tightly-sealing shoebox or sweater box. Then pack the rice or macaroni into a big paper envelope and staple that closed. the humidity will diffuse rapidly through paper.

A really big freezer bag with a double Zip-lock lip might keep humidity out. Humidity and oxygen can diffuse slowly right through standard, thin Ziploc baggies and their zipper.

But lots of people just store seeds for 3-5 years in paper and never worry about humidity!