Does seed go bad? A question we've heard a lot working in this business. It's somewhat of a complicated answer—but here goes . . .
If what you mean by "go bad" is that the seed will spoil, then no, it does not go bad. If a seed has not been properly dried, then yes, the germination rates will rapidly decline. Seeds that have not been dried are called crop year seeds. When a plant goes to seed, Mother Nature fully intends for that seed to sprout the next season; everything needed for the seed to sprout and develop is present in its little package—including a little moisture. This will cause diminishing results in germination. HOWEVER, when dried, seeds can stand the test of time!
All of the seeds at True Leaf Market have been put through a drying process that promotes longevity, including grains, flower seeds, herb seeds, and vegetable seeds alike. Albeit, there are several factors when storing and handling seed that can lead to germination decline. Keep in mind that the drying process does not make the seed immortal, but it does slow down the decline in germination substantially. If you're buying high-germ seeds, storing them right, and handling them with care, they should last for years to come. A great example of seed longevity is the ancient grain uncovered in Egypt nearly two centuries ago.
A type of ancient wheat seed called Farro (AKA Emmer) was found in ancient Egypt in the late 1800's, and after being sealed-off for hundreds of years, the seeds sprouted just fine. "Fifteen stems . . . sprung from a single seed," T.E. Thorpe said in an 1857 issue of Harper's New Monthly Magazine article after testing centuries-old grain. It just goes to show how tenacious seeds are when given the right circumstances for storage: cool, dry, and dark—the elements needed to long seed storage.
The most important thing to consider when storing your seeds is the humidity levels in your area of the country. Granted, the west lends itself to the storage of seed because of low levels of humidity, making seed storage ideal for us here in Salt Lake City. So, if you are at lower elevations where high humidity is more common, a few extra steps may be required to cultivate a dry place for your seeds. The quickest and easiest solution is to double-seal your seeds in two plastic baggies and place in the freezer—if you have bulk seeds a box freezer may be required. If you have a cellar or basement, it may be useful to look into ways to dehumidify that specific area. Understanding humidity control, allows you to create the environment that these seeds are designed to hibernate in for years to come.
Another misconception is that seeds will inevitably deteriorate after a five year period of storage—which simply isn't true. If germ problems arise with your stored seed, it is either a result of inappropriate handling or storage. By handling, we refer to missteps in the preparatory, planting, and/or watering stage of growing seeds, applicable to all growing methods. Some of these missteps can be using mechanical seeders that can damage the seeds, soaking seeds too long causing the seeds to drown, watering too much or not enough as seeds germinate, etc.. Even moving sealed buckets of seed from one storage area to another can be problematic when not handling the buckets with care.
Follow me on a quick tangent to address another distinction when it comes to "bad Seed".
The term "bad seed" gets thrown around a lot, leading to much misunderstanding as we've pointed out. In this case "bad seed" can refer to invasive species of plants that can harm and/or disrupt the ecosystem to which they are not native. A good example of this is purple loosestrife. Introduced to the United States in the 1800's for decorative and medicinal uses, it has had a substantial impact since then becoming a dominant plant in wetlands. So seeds can be "bad" when referring to their effect on an ecosystem—a very different meaning from "going bad" in terms of spoiling. Nevertheless, the distinction is worth noting and considering when assessing the status of your seeds.
Another example: Say, you want to plant peppermint in your garden this spring that has been stored in a cool dry place for a few years. You test it and germination is up to standard. So, it is ready for planting; however, peppermint can quickly take over a garden if planted in the ground with other herbs, vegetables, and flowers. Its invasive nature can disrupt the mini ecosystem of your garden, making it "bad seed" for that application. But, no worries! Just plant it in a container in your garden. Problem solved.