Seed Saving Time: Testing Germination Rates

 Testing seed quality and germination rates. showmeoz.wordpress.comShow Me Oz

Last week, I received my first spring seed catalog.  And while it’s a bit early for me to even think about ordering seed for next year, it is an early reminder to test some of the seed stock I currently have on hand. Checking the quality of the seed you save is just as important as saving it. After all, there’s nothing more disappointing than spending hours planting seeds that either germinates slowly, patchy, unevenly, or (gasp) not at all.  So, whether you save your own seed or lean heavily towards “accumulating” seed, you should be testing at least a portion of your stash every winter.

Seed banks employ rigid protocols to prolong a seed’s viability. They do this by carefully maintaining steady temperature and humidity levels favorable for the preservation of the seed embryo.  Most national seed repositories have the capability to store billions of seeds at subzero temperatures.

While home-based seed savers may not be able to achieve cryogenic conditions, you can still store seeds for a very long time so long as a few measures are taken to control as much of the environmental conditions as possible.

Packaging seed.

Seeds have a finite lifespan.  A few types, like beans and squash, will survive for years under the most suspect conditions while seeds like onion and chive are barely viable after only one year in storage.

The following table from The Garden Seed Saving Guide: Seed Saving for Everyone, gives a general overview of the number of years seeds are generally viable when kept in “very good” storage conditions – that is, cool, dark and dry.  But keep in mind that seed longevity can also depend on factors such as moisture content of the seed before storage, harvesting methods, packaging material, and so on.

  • Short (1-2 years): Anise, caraway, chive, cumin, leek, lovage, marjoram, onion, oregano, parsnip, peanut, salsify, sweet cicely.
  • Moderate (3-4 years): Beans (most common types), broccoli, carrot, celery, celtuce, chervil, corn, eggplant, fennel, ground cherry, leek, lettuce, parsley, parsley root, peas, pepino (melon pear), peppers, potato, tomatillo, tomatoes.
  • Intermediate (4-5 years): Asparagus, basil, dill, okra and Brassicas such as broccoli, broccoli raab, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, Chinese mustard, collards, garden cress, kale, kohlrabi, leaf mustard, mustard greens, radish, rocket, turnip, and rutabaga.
  • Long (6 + years): Artichoke, beans (Vicia and Vigna generas), beets, cardoon, celeriac, celery, chicory, cucumber (common, burr, Indian gherkin), endive, gourds, melons, orach, quinoa, spinach, squash, sunflower, Swiss chard.

Unfortunately, many seed savers fail to test their seeds for germination before planting in spring.  This leads to a colossal waste of time during what is already a very busy season. By testing, the gardener will know exactly how much seed to sow to get the results they want. This not only saves time, but it saves seed, too!

In another interesting twist, slow germination can also be caused by saving seed from too few plants. This is known as inbreeding depression, which is a condition of reduced genetic diversity expressed in various ways; the first of which is often poor germination rates.

Testing for Germination

To test germination lay one sheet of thick paper toweling on a baking sheet or large plate. Wet the paper towel until just moist, but not soaked or dripping. Place an even number of seeds on the towels, leaving a little space between each.  For home growers, sellers, breeders or those just wishing to save quality seed, testing 50 seeds is ideal, but 10 is enough to deduce whether further testing is in order.

Testing germination rates of melon and pepper seeds with a wet paper towel.

On top of the seeds, lay down another sheet of paper toweling and press it down lightly to remove most of the air pockets. At this point, you can leave it flat, fold it in half or roll it into a tube before placing it in a one-gallon zippered storage bag with one corner left unzipped.  Using a permanent marker, write the date, the common name, and the variety of the seed on the bag, and make a note of the average days to germination for that variety. Then, put the bag somewhere that is relatively dark and steadily warm (65°-70° F. ).

Testing seed germination rates.

Check on the seeds every two days.  Simply unroll the bag and count how many of the seeds have germinated.  Make note of this on the outside of the bag. Since most seeds germinate within 10-14 days, pay special attention to how many seeds have germinated by 7th, 10th and 14th days.

Testing seed germination rates.

All seeds that germinate after 14 days should be considered to have poor germination. From the total number of seeds that have sprouted by the 14th day, we can determine germination rates expressed in percentages. If 25 out of 50 (or 5 out of 10) seeds germinated in that time, that is a germination rate of 50% which puts you right on the threshold of poor germination.  For the home seed saver, a very good germination rate would be in the 80% range. And that’s easy to do when you save and store seed the right way.

Now, some flower and herbs are chronically poor germinators – that is, it’s built into their genes and can’t be changed.  However, almost all vegetable seeds are not built this way – and if healthy, seeds should germinate very rapidly and evenly given the right environment.

So when your new seed catalogs begin arriving, don’t order seeds until you’ve tested the germination of at least a few of your older seeds or those that have been kept in dubious conditions – and those you really don’t want to lose forever.  And, remember to grow out any varieties that you want to perpetuate but haven’t saved fresh seed from in a few years. This will keep your seed stock strong – and safe – for years to come.

Remember; it’s the vigorous seedling that turns into the season’s most productive plant!

Learn more about saving, storing and testing seeds in my book, The Garden Seed Saving Guide: Seed Saving for Everyone!

Happy gardening!

© 2015 Jill Henderson  Feel free to share with a link back to the original article.

The Garden Seed Saving Guide by Jill HendersonThe Garden Seed Saving Guide
Seed Saving for Everyone!

Save money, become more self-sufficient and avoid GMO’s by saving seeds!  This excellent resource for beginning and hobby seed savers takes you step-by-step through every aspect of saving your own seed in plain English.

Available in the Show Me Oz Bookstore
Look inside!

Jill Henderson is an artist, author, and the editor of Show Me Oz . Her books, The Healing Power of Kitchen Herbs, The Garden Seed Saving Guide and A Journey of Seasons can be found in the Show Me Oz Bookstore.  Jill is a contributing author for Acres USA and Llewellyn’s Herbal Almanac and her work has appeared in The Permaculture Activist and The Essential Herbal.

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One response to “Seed Saving Time: Testing Germination Rates

  1. Pingback: Seed Saving Time: Testing Germination Rates | Share the Seed

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