Further, as length of time in storage increases, the number and percentage of seedlings with damaging mutations or tissue degeneration also increases. Roots in particular are adversely affected by long-term storage. Large seeds must be dried longer than smaller seeds. When dry, corn and beans will shatter when hit with a hammer, squash seeds will break instead of bending. Seeds which pass this test are dry enough for safe short-term storage.
Most seeds benefit from drying with silica gel if they are to be stored for very long.
Seeds dried to a low moisture content with silica gel and then stored in a freezer can usually retain viability for many years. To use silica gels for drying seeds, place equal weights of silica gel and seeds to be dried in a well-sealed jar for 7 to 8 days. Then transfer the dried seeds quickly into airtight storage jars and place in a freezer, refrigerator or other cool, dark place. Carefully follow the instructions which come with your silica gels for drying them after use, to avoid burning them and rendering them useless. Silica gels suitable for drying seeds can be purchased from Southern Exposure Seed Exchange, PO Box 158, North Garden, VA 22959.