Vegetable Seed Viability

Wiese Acres Vegetable Garden

 As the water is pooling in the gardens from the melting snow, it's time to start getting ready for seeding season.  I ordered my new vegetable seeds a long time ago, but over the years I have learned that even though there is enough swiss chard or leaf lettuce seed in each packet to cover the entire county, it is not a good idea to plant it all at once.  So, there is always some seed left over for the next year.  There is nothing more disappointing, though, than to take the time and energy to plant seeds, eagerly wait for germination to occur, only to see nothing but black soil day after day after day.

To avoid that, it's always a good idea to keep track of exactly how old your seeds have become.  There are general rules of thumb for how long various seed types will remain viable, if stored in proper conditions.

Lettuce seeds are tough little things and remain viable for up to six years.  Seeds for cole crops, such as cabbage, cauliflower, broccoli, and kohlrabi will remain viable for up to five years.  Other five year keepers are celery, cucumber, eggplant, kale, muskmelon, radishes, rutabagas, spinach, squash, turnips and watermelon.  Oh - and the infamous swiss chard.  Beets, brussel sprouts, peppers, pumpkins and tomatoes last up to four years and beans, carrots and peas can remain viable up to three years.  Okra can last up to two years, but corn, onions, leeks, and parsnips are best replaced with new seed every year. 

Dill, basil and cilantro are long-lasting seeds, with viability up to five years after collection.  Parsley can last for up to three years, but most other herbs should be purchased or saved new every year or at least every other year.

All seed viability depends on them being stored properly in a cool, dry location.  If you collect your own seeds, they should be dried well before storage and then stored in a dark, dry envelope or container.

If seed is a left-over from previous years, or if you save your own seed, it's a good idea to do a germination test before planting.  You can do this with all seed, but it usually isn't necessary with newly purchased seed since the companies test germination of batches before packaging.  To do your own germination test of small seeds, moisten a paper towel, fold it in half, then place a few seeds on one half of the half.  Carefully fold the other half over the top of the seeds.  Seal the paper towel and seeds in a plastic bag and place it in the conditions recommended for germination for that particular seed type, for the length of time it generally takes for germination to begin.  For example, if the seed requires warm, dry conditions for 7 to 10 days to germinate, place the plastic bag inside a darkening paper bag and place the entire package near a heat source.  After seven days, carefully unfold the paper towel and check for germination.  If the majority have germinated, you're probably ready to plant them in your garden.  If germination is poor, wrap them up and give them the additional three days or so that it might take them to germinate.  After that time, the germination is probably as good as it's going to get.

I always try to test germinate a quantity of seeds that is divisible by 10.  That makes  it easier for me to determine a percentage of germination.  If I test 10 seeds and one germinates, I have a 10% germination rate.  My rule of thumb is that if the germination rate is 75% or more (for most seeds), I'm good to go.  If the germination rate is 45 to 75%, I'll still plant but will seed more heavily to make up for poorer germination.  If the test germination rate is less than 45 to 50%, I will just throw the seeds and buy new.  I don't believe in doing useless work.  :)

For large seeds like peas, beans, and corn, you can test for viability by immersing them in a bowl of room temperature water.  If they float, it's because they do not contain the weight of an embryo and are sterile.  If they stay on the bottom submerged in water, they are likely viable.

Armed with viable seeds, I'll be ready to get those vegetables growing - as soon as the snow is gone!