By Connie Kotke, Master Gardener
As seeds get older, their viability (whether or not they will germinate) decreases. For some flowers and vegetables, you’ll want to plant fresh seeds each year. Other varieties can be stored in a cool, dark place and used successfully for several years. Here’s a simple test to see if those old seeds will work!
Testing Seed Viability
Old seeds you’ve stored may germinate this season, depending on the variety and conditions in which the seeds were stored. Those kept in a warm, humid place will deteriorate faster than those kept in a cool (32 to 41 degrees) and dry spot. All seeds become less vigorous as time goes by; even if they germinate, they may grow slowly and have a tough time producing flowers or veggies. The longest you can keep seeds is 5 years for vegetables like beets, tomatoes, cucumbers, lettuce, and muskmelon.
Try this simple method to check the viability of your stored seeds:
- Count out 10-20 seeds.
- Lay them on a wet paper towel and fold the towel over until they’re covered. The seeds should not touch one another.
- Place into a plastic storage bag and store in a warm place.
- Check the paper towel after 2-3 days and then every day thereafter; spray with water to keep moist.
- After the standard germination time (noted on your seed packet), open the paper towel and see what percentage of seeds have germinated. If the rate is high (at least half), you can use the seeds.
We recommend storing seeds in an airtight, watertight container such as a jar with a rubber seal or a plastic storage bag within a regular jar or container. Your refrigerator or freezer are ideal.
For more information, click on these links for University of Minnesota Extension resources: