|What is the proper way to store seeds for long-term (say, about 5 years) so as to maintain maximum viability?
|The best way to store seeds is to keep them dry and at a moderate, even temperature. Many gardeners keep them in an air tight container in the refrigerator. Be sure they are dry and pest-free (and dated and labeled) when you put them in. Some people add a small envelope of antidessicant, such as those occasionally found packaged with new camera equipment and the like, but this is not strictly necessary. Some gardeners also find it handy to keep a running list of the seeds for easy reference.
You should be aware, though, that the viability time frame varies from plant to plant. Some, such as tomato seeds, will last about five years. Others, such as lettuce, will not keep very well regardless of storage method. If you use older seed, even if it is within the average viability range and has been stored correctly, you should expect increasingly poor germination from year to year.