Tag Archives: seed viability

Older Seeds-how to test for viability

seeds

If you have gone through your seeds and find packets that are over 3 years old, you may want to test them for viability. Are they still good enough to plant again? Many seeds are good for 2-3 years and some much longer if they didn’t get wet or damaged. I grew the state record for giant green squash (345 lbs) from a seed that was 8 years old. I was amazed. Read about the giant green squashes here; https://giantveggiegardener.com/2011/10/04/greenies-battle-it-out-for-who-will-go-to-the-weigh-off. So sometimes older seeds are fine too. Here are some things you can do with older seeds.

  1. First,  if they are over 3 years old I may toss them in the ground later in spring (especially flower seeds) to see if they germinate or
  2. I may test the seed packet (look at the date on the package) to see if they are still viable. Three years or older? Test them. To test them, take 10 seeds and soak them in water for a few hours to overnight and then put them in a damp paper towel and put them in a Ziploc bag and on a shady, warm windowsill or on top of your refrigerator (not a sunny place, you don’t wanna fry the seeds). Then in a few days check them to see how many have germinated.
  3. I use this chart  “Germination tables from Heirloom Seeds – Know when to plant all your vegetables.” to see how long it should take to germinate a particular seed under ideal conditions.  If none have germinated, keep checking them. After a few days, you’ll see some of them have germinated. So if 8 out of the 10 germinated, you have a 80% germination rate. If 5 out of the 1o seeds germinated, then you have a 50% germination rate, if only 2 have germinated than you have a 20% germination rate and so on.  I would probably toss those. This chart is also great to have when we are actually ready to start seeds inside under lights or directly outside (later) to see what is the optimum soil temperature is for each seed and how long it will take to germinate. I will post later on that when starting seeds inside or outside. This is just to test for seed viability right now.