2. Store seed properly to maintain viability
Seeds are a fragile commodity, and if not treated properly, their viability will sharply decline. While some seeds may survive for thousands of years under the proper conditions, others will lose viability quickly, even when properly stored. To maintain dormancy, keep seeds in a cool, dark location with low humidity, like a refrigerator. I recommend labeling them (seed name, source, year) and storing them in a small reclosable bag or empty film canister that is, in turn, kept in a larger plastic container. Once you are ready to sow, you can test the viability of many, but not all, seeds by soaking them in water for a few hours. The seeds that are still living will sink to the bottom, while the dead ones will float on the surface. This test generally works better for larger seeds, but there are no absolutes.