Seed Germination Test
With the recent sunshine and warmer weather, your mind might be turning to starting seedlings. While flipping through stacks of seed catalogues is admittedly one of my favourite ways to spend an evening, what about all of the seeds I have already accumulated from years past? Can those still be planted or should I throw those out and buy new?
While the idea of using existing seeds is enticing, it’s important to ensure that the seeds are still viable before planting. Nothing is more disappointing than to have just a few stragglers pop up in your carefully tended row after putting in the work of seeding and watering.
Enter: Seed germination percentages.
Seed germination percentages are the percentage of seeds that are likely to germinate given correct growing conditions.
Correct growing conditions can be found on the seed packet or seed company website.
Sometimes seed companies will state the germination percentage on the seed packet. A seed packet that indicates a 95% germination percentage means that 95 out of 100 seeds will germinate given correct growing conditions. This is good information to know, so that you can plant extra seeds accordingly to end up with the final number of plants that you need in your garden.
It’s important to note however that the germination percentage listed on a seed packet is only accurate for the year that the seeds were packaged (also usually listed on the package). Every year that passes, the germination rate will drop. So we need a method of testing germination percentages at home for both older packages of seed and open-pollinated seeds that have been saved from your garden.
Luckily, seed germination tests are easy and inexpensive to do at home and they produce accurate results.
To perform a germination test, fold a paper towel in half twice so that it creates four layers. Wet the paper towel and wring out any excess water. You want the towel damp but not dripping wet. Remove some seeds from the seed package and place the seeds on the paper towel. This is a test of percentages, so the larger your test batch of seeds, the more accurate your results will be. Slide the damp paper towel and seeds into a plastic bag and seal. Place this bag in a warm location where you can check on it every day. The length of time to germinate will depend on the species you are testing, so refer back to the seed packet for an indication of how long it should take. Once the seeds have germinated you can count the duds and do a little math to figure out the germination percentage.
On my test of the Delphinium ‘Magic Fountain’ seeds that were collected from our fields in 2020, only 30 seeds sprouted from the 56 that I tested. This is a 54% germination.
If a test indicates a low percentage, I would recommend replacing these seeds unless they are an extremely rare variety. Which leads back to that stack of seed catalogues calling my name…
If you’re looking for me, I’ll be curled up on the couch with a mug of tea, surrounded by dog-eared seed catalogues.