Skip to content

DUCHESS OF DIRT: Run a germination test on your older seeds to confirm viability



Special to the Record

Nothing gets me more excited about a brand new year than the imminent arrival of a new gardening season.

By January I have had more than enough of the endless grey, damp, cold days of winter weather. I am a spring-loving person and rounding the corner into a new year has me impatiently counting the days to the spring equinox. About the only things that save my sanity are the necessary chores to get ready for gardening season and the seed catalogues arriving in my mailbox.

I have finished sorting through my stash of seeds and turfed any that are over five years old. Since I am not always meticulous in how I store my seed packets I must do germination tests on any seeds that are three years or older. Any two-year-old pepper seeds must also be tested as their viability is now questionable. Same with two-year-old onion and leek seeds, as most references list onion species as viable for one year.

I find the easiest and most space-efficient way to do germination tests is to use paper towels and ziplock bags. Depending on how many leftover seeds I have of any one variety, I will place five to 10 seeds on the paper towel, wet it slightly, gently squeeze out any excess, and place the folded towel in the bag. Of course, I have already labeled the towel, using an indelible pen, with the name of the seeds in that towel. Heaven help if you forget and are testing multiple cultivars of tomato seeds, for instance. Not a good way to start your gardening season, believe me!

I make a list of the seed varieties I am testing and the number of seeds in each towel. A week later, I check each bag, carefully unfolding the damp towel, and count the seeds that have germinated. If the number is low, I put the towel back in its bag and check it again a week later. When you think all the seeds have germinated that are likely going to, it is then an easy calculation to determine the germination rate of those older seeds.

Some seed companies will state in their catalogues what the typical seed germination rate is for the current year’s seed. If it is not stated, I figure I am doing well if 75 per cent of the fresh seed germinates, but usually it is higher. With older seeds, I look for 50 per cent germination rate, but will accept as low as 40 per cent if it is a favourite F1 variety that I have not been able to replace with fresh seed.

Once I have an idea of how viable my older seed is, I start working on my indoor seed sowing schedule, paying particular note to the last frost date in our garden.

This can sometimes be tricky. Our last frost date was April 20 but we did have four days in May with an overnight low of -1 C. The latest was on May 14. Also had hail on April 26. Similar scenario in Spring 2021: -0.5 C on May 19 and hail on March 26.

The “joy” of gardening in a changing climate. Unpredictability. Is it this challenge that keeps us planning our advent into the garden each year? I asked John this question.

Leslie Cox co-owns Growing Concern Cottage Garden in Black Creek. Her website is