If I have forgotten my seeds outside in my non heated garden shed, would they be ok to use this spring?

Yes, they should be fine, as long as they're dry.

Karen

gardendreamer is in Calgary and it has dipped to -30C, which is -22F this season. some seeds may not have been affected, but the best way to check is test germination of say 4 seeds in a damp paper towel

Thanks Joanne, I should figure out how to add that information for others to see
Thanks for the tip and I will try that out.

I agree that "dry" is the most important thing for long-term seed storage.

I read about a cheap way to tell whether the inside of a seed jar or box is good and dry. Keep a few strips of newspaper in each jar or bag. If the newspaper is dry enough to crackle when bent and folded, it is quite dry.

If it flops round limply and silently when you finger it, it isn't very dry.

You can also buy humidity-indicating strips for 25 cents, or a one-dollar strip that has different indicating dots for 10%, 30%, 50% and so on.

Seeds "should" be stored well below 30% relative humidity, based on what I read, and I've seen 5%, 8% and "less than 10%" reccomended.

Corey

I store my seeds with a little dessicant, in screw-lid plastic tubs that used to hold two pounds of peanuts or peanut butter.

I put 2 tablespoons of silica gel (used for drying flowers) into a paper coin envelope and staple it shut so it doesn't leak out. One coin envelope of silica gel keeps one tub dry for months if I don't open it too often in humid weather.

My silica gel is much too fine to put into organza bags: the dusty part sifts right through it. But humidity passes freely through paper.

When a packet has absorbed too much water, the blue "10%" indicator dot turns pink, and the 30% dot starts to change color. Then I replace that tub's coin envelope with a fresh one full of dry dessicant.

When my pound-and-a-half of silica gel has all been used up, I'll pour all the coin envelopes out into a shallow metal pan and bake it around 400-450 F for several hours to regenerate it, then seal it tightly and use it again. I expect this batch to last me some years, keeping 6 - 8 tubs of seeds dry in the Pacific NorthWet.

If I trusted my oven to stay over 400 but under 451 F, I might try leaving the silica inside the paper envelopes while drying them, but I would expect to scorch or char the paper and glue (and melt the scotch tape that's on some of the envelopes).

The silica gel only cost me $7-8 at a craft store in the "dried flower" section. It was cheaper than "Drierite" and it seems to last longer, as if it had greater drying capacity.

If you have a choice, a coarse grade might be better than fine, to reduce the amount of silica dust while you're pouring it into or out of paper envelopes. The fine, dusty grade is so potent that it dries a tub right down below 10% in just a few hours, so "coarse" should be good enough.

The silica "gel" has the consistency of fine, dusty sand whether it's fully dry or pretty hydrated.

Corey

In the last few months, I heard about using dry rice as a seed dessicant. You can even mix it in with the seeds and pull it out later with a seive!

You can make a more powerfull dessicant or "regenerate" the rice by baking it in a shallow pan and sealing it tightly in glass jars while still hot.

I tried to get an estimate of "how hot?" but all I got was was "you don't want it to get brown" and "bake it longer, rather than hotter".

My guess is around 250 F.