The United States Department of Agriculture (USDA) requires that seed germination rates be tested at least once a year. A “sell by date” is also required on seed packets and cannot date more than a year from the last passing germination test. Sow True Seed tests the germination rates of all seed varieties twice a year via the North Carolina Department of Agriculture to ensure passing germination rates. The sell by date is not a “use by” date; most seed varieties, stored properly, can last up to three years. Sow True Seed stores all seed varieties in a climate controlled facility that averages 50° F and 50% humidity, which are ideal seed storing conditions. For the home gardener the best way to store seeds is in the refrigerator, in a zip top bag or Mason jar, with silica packets to absorb any moisture. We do not recommend storing seeds in the freezer.