Big Mason jars sound great. The rubber gasket is air-tight for months.
The downside is that once the Mason jar lid is sealed, NO humidity will be pulled out of the jar by the Eva-Dry Rechargeable Dehumidifier (looked it up - really cool!) The chest will still keep temps steady and maintain darkness.
You could rely on the hope chest seal being tight enough that you would not need to recharge the Eva-Dry very often. Then you would not need tightly-sealing Mason jars (the seal would be the chest itself). There has to be an open or slightly open path between the seeds and the Eva Dry, then a seal surrounding both seeds and Eva Dry.
Or, as you say, a little desiccant and an indicator card in each jar, and seal the lid tight. That makes the Eva Dry redundant.
To be very careful, you could use silica gel "wherever" until it absorbed a little humidity. Or, when you recharge it, don't get it totally dry. Then its maximum drying capacity is reduced and it would only be ABLE to pull RH down to 15-20 instead of 5-10%. Then you'/d be very safe putting some inside a sealed jar.
Or maybe a thick plastic bag containing the open seed jars and the Eva Dry could be put inside the hope chest and sealed as well as practical.
>> Do I remember correctly that you have an engineering background?
BS in biochemistry, worked around one year in tissue culture cancer research as a lab tech, then technical and engineering jobs. Right now, software engineer for airplane braking systems. Worked on anti-skid software for the Boeing 787. Fun stuff!
Corey
