Understanding Seed Expiration Dates
If you look on the back of your seed packet, there should be some type of dated information, at least with most reputable sources. For example, it may have a “packed for” date, which is typically when the seeds were packed, not necessarily when they were harvested. As with many items you find at the grocery store, you may have “sell by” or “best by” date, which normally indicates the end of the year those seeds were packed. Additionally, many seed packages include a “sow by” date, which doesn’t represent the freshness of the seeds but rather the resulting validity of a germination test previously conducted prior to packaging. While some may wonder whether or not it is safe to plant seeds that have passed their expiration dates, we know that planting expired seeds will not impact the outcome of the final plant grown from that seed. So, will expired seeds grow? Yes. Plants grown from expired seed packets will grow to produce healthy and fruitful harvests, just as their younger counterparts. With this in mind, one may be left to wonder then, when do old seeds expire? More importantly, why do we need seed expiration dates? Although seeds do not technically “go bad,” expiration dates are used on seed packaging as a measure of the likelihood that the seeds will be viable. Depending upon the type of seeds, environmental conditions, and the manner in which the seeds have been stored, the germination rate of older seed packets may be greatly impacted. The best storage conditions for seed packets require a dark, dry, and cool location. For this reason, many growers choose to store plant seeds in airtight jars in places such as refrigerators or in cellars or basements. Many may also add rice grains to the jars to discourage the presence of moisture. While proper storage conditions will help to prolong the lifespan of seeds, the viability of many types of seeds will begin to decline regardless. Some seeds will maintain high germination rates for up to five years but others, such lettuce, will lose vigor as soon as one year in storage.
Are Old Seeds Still Good?
Before planting with expired seed, there are some steps to take to check whether or not germination will be successful. When wondering, “will expired seeds grow,” gardeners can conduct a simple germination test. To test the viability from a seed packet, simply remove about ten seeds from the packet. Moisten a paper towel and place the seeds into it. Place the damp paper towel into a zip-lock bag. Leave the bag at room temperature for ten days. After ten days, check the germination of the seed. Germination rates of at least 50% indicate a moderately viable packet of seeds.
