This is the time of year that the first seed catalogs for the new season start to arrive in mailboxes. For gardeners, this annual ritual often sparks excitement and inspiration, but it can also lead to the discovery of a drawer, box, or jar filled with leftover seeds from previous years. If that sounds familiar, now is an excellent time to test those older seeds to see if they are still viable or if it’s time to replace them.

Testing for seed viability is a very simple task and requires very few supplies and no special growing environment. The goal is to provide consistent moisture for several days. You want just enough moisture to encourage germination, but not so much that the seeds rot before they sprout.

One easy method is to place a couple of damp paper towels in a shallow glass or plastic container, saucer, or small food-storage container. Lay several seeds on top of the paper towel. While the exact number and placement of seeds is not critical, using a specific number like 10 or 20, makes it easy to calculate a germination percentage later.

Cover the seeds with another damp paper towel and loosely place a lid over the container. The lid does not need to be airtight, but it helps reduce moisture loss and keeps the paper towels from drying out too quickly. Light is not necessary for this test since the goal is simply to assess seed viability rather than grow a plant.

Check the seeds daily for signs of germination and to ensure the paper towels stay moist. Some seeds will germinate quickly and fairly uniformly, while others may sprout sporadically over several days. If seeds germinate one or two at a time, it can be helpful to remove them as they sprout to reduce the risk of fungal growth. Be sure to count the removed seeds as viable.

If your test reveals a lower-than-expected germination rate, don’t be too quick to discard the seeds. These seeds can still be used successfully by planting several seeds to compensate for reduced viability. Knowing the germination percentage simply allows you to plan more accurately and make the most of the seeds you already have on hand. And may free up some “seed” money so you can try new and different varieties.