Learn to Test Old Seeds and Save Them the Right Way

Every year my seed catalog eyes are bigger than my gardening effort and I end up purchasing more seed than I use. I keep this seed in a simple box and every year I wonder whether it is still good for planting.

There are the old standbys that I plant every year – broccoli, lettuce and pumpkin and I also try to purchase seed for something I’ve never grown before. That means I always have a bunch of left over seed. This year I’m going to be smarter about my seed storage. For now, it’s time to weed out the old, see what’s still viable, and order new seed.

How Long Will Seed Last?

As a general rule seed stored at room temperature will still be viable after one year. So last years seeds are still good. You can extend that for up to 10 years under certain circumstances (which I have not followed!) by paying attention to the seed moisture content and storage temperature.

What’s the best way to store your seed? Make sure your seeds are completely dry and place them in a paper bag and then in a mason jar with silica at the bottom. The drier the seed the longer its storage life will be.

These are the general guidelines for storing seed if you have been moderately careful about their moisture exposure:

How To Test Old Seeds for Viability

This is the time-tested method for proofing old seed. It can take as little as three days and as long as two weeks, depending on which seed you are trying to germinate.

You will need:

• 10 seeds
• Paper towel
• Plastic zip bag or mason jar
• Water

1. Thoroughly wet the paper towel and fold it in fourths.
2. Put your 10 seeds inside the paper towel; make sure the seeds are not touching.
3. Place the wet paper towel inside a plastic zip bag or mason jar.
4. Cool weather crops should be kept between 50 and 70 degrees. Warm weather crops need to be kept between 70 and 85 degrees.  Light is not necessary.
5. Check the package for average sprout time and check back after a few days.

Once they’ve sprouted do the math – 10 seeds sprouting is 100%, 9 seeds is 90%. Even 50% germination will work, just compensate by sowing more seed. Anything less than 50% will probably not be worth your effort.

Be frugal about your seed purchases this year. Save them properly for the future and test those old seeds before you take the time to use them. Happy planting!