Answer: Generally speaking, seed viability decreases over time and results in decreased germination, regardless of storage conditions. Keeping them cool and dry is about the best you can do; the refrigerator is a good place to keep them. In addition to keeping them in sealed containers or jars you might consider adding some silica (such as those packets occasionally included with new cameras or leather goods). Be sure the seed envelope is also dry when you put them into storage. Finally, be sure to label and date each batch of seeds and keep a log. This will help you predict when to replace your seeds. Tomato seeds are particularly long lasting and so a few might make the 5 year mark; most others will not.
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