Winter Sowing: growing native plants from seed for free 

Native seeds need the cold of winter and the moisture of snow to germinate, a process known as cold stratification. This process breaks the seed dormancy, and the seeds will sprout when temperatures warm up in spring.  

Photo: Christina Keys 

Winter sowing: growing native plants from seed for free  

By Christina Keys 

After moving into my new home in the spring of 2021, I set about identifying the plants in my garden. The last to identify was the most spectacular pink New England aster (Symphyotrichum novae-angliae), which bloomed from August to early November. I knew I would expand the garden space, so I wanted to learn how to grow more of these beautiful plants from the fluffy seed heads that formed. I soon discovered the world of winter sowing, a local community passionate about growing native plants from seed, and the enormous ecological benefits to planting native species.  

That fall, I picked up a dozen free seed packets at the Ottawa Wildflower Seed Library seed-giveaway events. This “library” allows you to take seeds or seedlings for free with the hope that you will donate back seeds from the mature plant in future years. It is a grassroots non-profit organization run by volunteers across the region. It promotes gardening with native plants to provide habitat for bees, butterflies, birds and more. Following their instructions, I have grown hundreds, maybe thousands, of native perennials and grasses in a few dozen containers on my deck over winter.  

The steps to growing plants from seed over winter are surprisingly simple and easy. Most native seeds need the cold of winter and the moisture of snow to germinate, a process known as cold stratification. This process breaks the seed dormancy, and the seeds will sprout when temperatures warm up in spring.  

This fall, seeds for native perennials, grasses, sedges shrubs, and trees will be available for free at events across the city including in Centretown and Hintonburg. Volunteers will be on site to provide advice on choosing suitable seeds for your garden conditions. If you have garden space to fill or want to remove some lawn to have more flowers, here are the simple steps to follow:  

1. Check your site conditions to choose your plants. Shade, part sun or full sun? Moist, average or dry soil?  

1. Get some pots and potting mix. Each pot will need drainage. Use plant pots or drill holes in plastic fruit, salad or yogurt containers. Fill with moistened potting soil.  

1. Sprinkle seeds on soil. Gently push so each seed makes contact with soil. Add a little more soil on top if the packet instructions advise it. 

1. Label each pot with a garden marker (e.g., Staedtler). 

1. Place outdoors. Cover with row covers or old screens to protect from squirrels.  

1. Once the snow melts, keep the containers watered. Watch for tiny seedlings to emerge. 

1. Thin seedlings so that each has enough space to grow. Alternatively, separate each out into small pots.  

1. Once three to four inches high, plant in your garden. 

This method has excellent germination rates, helps to prevent seeds from washing away or being eaten by wildlife and allows gardeners to place plants according to their garden design.  

With winter sowing, I’ve converted my whole property into a colourful, wildlife-friendly haven on a tiny budget. Some flowered in their first year, including spotted bee balm, blue vervain and little bluestem grass. Others needed another year or two to establish roots before flowering.  

A special thing about New England asters I’ve learned from growing them from seed is that they have a natural variation in flower colour from deep purple to hot pink to white. I now have a few dozen new aster plants around my property, each a unique colour, and as they bloom, they are providing nectar and pollen for native bees prior to hibernation and for migrating butterflies like the endangered monarch.  

It’s hard to decide what has brought me more joy – seeing the first green sprouts emerge from the pots in the spring or watching my eight-year-old marvel at my garden’s busy bees, wasps, butterflies and birds.  

Pick up your own seeds from the Ottawa Wildflower Seed Library at events across the city this fall. See https://wildflowerseedlibrary.ca/events/.  

Christina Keys is a wildlife gardener with Garden ReLeaf, a Glebe-based ecological garden restoration and design company led by Tara Beauchamp.