I'm very envious of your electrically rechargeable desiccant! Is there a product name or company name I can look up?
>> To check that they were actually working and would change ...
Science or engineering background? Clearly you know exactly what you;re doing!
>> WHERE do you store them?? I see they're in a cardboard box, but WHERE?? Would my closet be okay? or my hope chest ( a humidifier strip says it's a bit higher than my crisper but still in the 20% spot)
I wish I had a consistently cool spot, but decided not to use any part of my fridge or freezer because condensation wierds me out. Instead I just rely on the fairly constant temperature in my living room, and it never gets VERY hot there. Since I always seal the tubs as tightly as I can, I don't worry about varying humidity in the room air. They leak, but very slowly.
I think either spot you mentioned would be OK, wherever the temperature is more consistent and lower. Apparently "darkness" is the third variable in viability duration. Steady dryness is the most important variable, and steady, low temperatures after that.
I would lean toward the hope chest, since that might seal at least a little, and hold the dry air inside a little longer than the closet would. And the chest is smaller than the closet.
>> still in the 20% spot
If you have a desiccant and the seeds are sealed in with it, the room humidity doesn't matter much. If the seeds and desiccant are in an open bowl, then the driest spot you can find or create will let you regenerate the desiccant less often and keep the seeds more uniformly dry. All the desiccant can do is dry out the air that touches it. Your mission is to keep that dry air near the seeds, and not letting it diffuse away in an attempt to dry out your entire house.
Maybe put the bowl and desiccant into some large tub like a plastic sweater box or under-bed storage bin. Improve the seal as much as you can, maybe by laying thick plastic film over the top before you clamp the lid on over the plastic film. Just, if you get a really tight seal, keep an eye on your high-quality humidity cards (I'm envious of them, too) in case the overall humidity dips below 15% when the desiccant is freshest.
>> still in the 20% spot
Wow, your room air is ALWAYS that dry? The most that a desiccant can do for you is keep the seeds 5% drier than they would have been anyway (15% RH instead of 20% RH).
>> Stored seed's viable life span approximately doubles for every 10% reduction in seed eRH.
Kew's idea that you gain twice the lifetime for each 10% RH reduction (down to 15% which is optimum for long-term storage) hints that the "viable lifetime" difference between 20% and 15% RH might be (guessing) around the square root of two, so say seeds stored at 15% RH might last 40% longer than seeds at 20%.
I thought I remembered your name from the Piggy Swap, but I remember now that you skipped the usual "kill hundreds of seedlings" step by just doing the opposite of everything I had done for my first two years. That really made my year! it suggests that I might have found EVERY possible way to kill seeds, and in just two years!! (proudly, kind of)
Or you're just very good at it. I'm guessing a scientific or engineering degree or career.
