You may think you’re saving money by using seed left over from previous years. Sometimes, however, using leftover seed can lead to failure and frustration, leaving you no option but to purchase seedlings, which defeats your purpose! Here’s how to determine when it’s a good idea to use old seed … and when it isn’t.

1. Check the dates on your vegetable and flower seed packets. Most but not all seeds that are 3 years old or less should germinate adequately, assuming you’ve stored them in a cool, dry space. However,

  • If flower or vegetable seeds have been stored in a garage or shed where temperatures and moisture levels fluctuate wildly, it’s a good bet that you won’t get good germination. To be safe, test or toss them.

  • Some seed types inherently have greater longevity than others. Cucumbers and cantaloupes, for example, can be stored for 5 years. Parsnips and onions need to be purchased every year.

Tip: Some seed packets are not dated. Remember to date them at time of purchase, if necessary.

2. Sort vegetable seeds and check them for longevity using the chart below.

Longevity Chart of Selected Vegetable Seeds*

* Adapted from Federal and Colorado relative longevity of selected vegetable seed

3. If you’re in doubt, this simple germination test will help determine if seed is worth planting.

  1. Dampen a few layers of paper towels and spread 10 seeds over the surface, using separate towels for each seed type.

  2. Roll the damp towels, with seeds inside and stand them on end in a jar.

  3. Label the jar and place it in a warm place.

  4. After 3 or 4 days (or the germination time specified on the seed pack) open the rolls. If seeds have not yet germinated, wait another several days.

  5. If germination is less than 70%, sow more thickly than recommended; less than 50%, buy new seed.

Remember that storage conditions make a big difference when it comes to seed longevity! For best results, seeds should be stored in a cool, dry, dark space in a tightly sealed container, such as a mason jar. A temperature of 40°F (5°C) is ideal, but if that’s impractical find the coolest, driest space you can, such as an air-conditioned room or an unheated closet.

Tip: Put a few of the silica gel packets that come in new product packaging to use—add them to your seed storage containers to absorb excess moisture.