Most seeds will store for 2-4 years if kept clean, cool, dry, and out of light. However, some seeds will badly deteriorate after about one year if not stored in an airtight container in the freezer or refrigerator. These include: onions, leeks, parsnips, celery, spinach, salsify, and hybrid supersweet corn. For long-term storage, place seed packets or bulk quantities of seed in a large, airtight container (such as a mason jar with a 2-piece lid) and store in the refrigerator or freezer…