(Dr Laurent Legendre - February 2003 - )
Place all of your seed packs in a tightly closed, large, plastic ware that you will store in your refrigerator (4C). Some protocols ask for the addition of a desiccant (water catching chemical) in the plastic container to keep the air dry inside. I’ve had mixed results with this technique and have found that the seeds store longer if the desiccant is omitted.
When you want to remove seed packs from their plastic container, leave the container for 5 min at room temperature before opening it. This will momentarily warm up the seed packs and the container to prevent moisture from condensing on them.
The maximum storability of seeds under those conditions has never been experimentally tested. From my experience, it seems to vary between a couple months to a couple years depending on the species and factors of which I do not know the nature. My record is 5 years with some P. caerulea and P. vulgaris seeds.