Factors

Seeds need to breathe. Cold storage slows down their metabolism, but they would not survive if unable to breathe. An air tight container in a cool dark basement with plenty of silica gel is perhaps the best solution. Avoid drying out the seeds, but we also need to avoid too much moisture that might cause the seeds to rot or to try to germinate prematurely. Basements or root cellars will cover the requirement of a cool, dark environment, but they are generally high in humidity (usually in the 60 to 75 % range - too high for seed storage). One could use a cabinet to organize the seeds in containers and spread silica gel over the bottom of the drawers to reduce the humidity in the cabinet. Eventually it will be necessary to exchange the silica gel, but it can be dried and reused so this is not a problem. I purchased a 5 pound can at Walmart for under $10. There is enough silica gel in this can to cover two drawers (roughly 1/4 inch of silica gel). They also sell larger cans.

Offered by Roger.