What a wonderful time of year to be a gardener! The mailbox overflows with seed catalogs showcasing what is new for 2020. I also find myself looking at the 78 seed packets I already have—most great performers from past years—and see some were “packed for use in 2015” or even earlier!
It’s time to decide if you need to buy new seeds; we can plant onions and peas outdoors as early as mid-February and if you grow your own transplants, you’ll want to start planning, too! For example, tomatoes will need 4 to 6 weeks before the last frost to grow to transplant size, so you’ll need to start them indoors early to mid-April here.
Must I buy seeds packed for 2020 and throw away these old favorites? Not always—many seeds are viable for years. The Chicago Botanic Garden provides some general guidelines for vegetable seeds: http://my.chicagobotanic.org/wp-content/uploads/Seed-Viability-Chart.pdf
So, for example, if you have cucumber, pumpkin, or squash seed from 2014, you might be fine, but onion, leek, parsnip, or parsley seeds from 2018 may already be worthless!
Testing seed viability
If you want to test your own seeds, Ward Upham, Kansas State Master Gardener Coordinator, suggests the following quick and easy test for each type of seed you want to test:
Place 10 seeds on a paper towel moistened with warm water and cover with a second moistened towel. Roll up the towels and place inside a plastic bag with enough holes for air exchange but not so many that the towels dry quickly. Place the bag in a warm place such as the top of a refrigerator. Remoisten towels with warm water as needed. After the first week, check for germination. Remove sprouted seed and check again after another week. Add these numbers together to determine the percent germination.
Planting old seed
If your old seed is still viable, you can simply plant extra seed in anticipation of lower germination rates.
The best places to store your seed are where it is cool and dark, such as the refrigerator or a cold basement. If you save seed from your garden, be sure the seeds are dry before you store them. For purchased seeds, keeping them with their original packets allows you to quickly determine the contents. Seal seeds in an airtight container, such as a canning jar, to prevent moisture.
Article by Bob Wardwell, Extension Master GardenerSM Volunteer
For more information:
Vegetable gardening planting times: https://extensiongardener.ces.ncsu.edu/wp-content/uploads/2016/07/NC-Vegetable-Planting-Guide-1.pdf?fwd=no
**Note: Planting times for Western North Carolina Mountains are in purple and times to harvest from seed are indicated in the left-hand column. Those with an “*” should be started indoors rather direct seeded in the garden.**
Tips for growing plants from seed: