Kent Gardener Maggie L. Moor-Orth explains how to see if old seeds are still viable, and what to do with them.


April is fast approaching and many of us will soon have our gardens amended and prepared for the new growing season.

If you are like me, you have seeds left over from last year, the year before and some seed packs dating back four or more years. When you have old seed packs, you have to ask yourself, “Should I plant these, throw them out or test them for quality and germination rate?” My answer would be to test them. I remember my dad testing seeds in our kitchen before he would make any decisions on their fate.

To do a germination test, count out 10 to 20 seeds, then spread them out on several layers of moistened paper towels. Carefully roll them up in the paper towels so the seeds do not touch one another. Place the roll in a plastic bag (this keeps the moisture in), twist-tie it shut and keep it in a warm spot. Remember to label the roll or bag with seed variety and mark the start date of the test. Then, every three or four days, carefully unroll to see what is sprouting (evidence of a root or cotyledon structures protruding from the seed.) Keep in mind some seeds take three or more weeks to germinate. After a week has passed and no additional seeds have germinated, it is time to count the germination rate.

If you started with 20 seeds and 10 have sprouted, you have a 50% germination rate; if five seeds germinated from the 20, then you have a 25% germination rate. Let’s say you start with 10 seeds and only two have sprouted; then you have a 20% rate. If five of the 10 sprouted, you have a 50% germination rate. You can now decide what to do. If I had a 50% germination rate, I would still use the seeds, and just plant twice as many.

So how long are seeds good or viable? The following is a guideline of seed viability stored under dry, cool conditions.

Parsnips: 1 year Okra corn and peppers: 2 years Beans, carrots, leeks and peas: 3 years Beets, mustard greens, pumpkins, rutabaga, squash, Swiss chard, tomatoes, turnips and watermelons: 4 years Broccoli, cabbage, Chinese cabbage, cauliflower, celeriac, cucumbers, eggplant, kale, kohlarabi, muskmelons, radishes and spinach: 5 years

    If you are like me and have retrieved your seed storage box for planting this year’s garden only to find leftovers you think may have to be discarded, why not test their germination rate first? And if you are lucky, they will germinate and grow for you again this gardening season.