By Candy Venning
shared with permission from The Halton Master Gardeners Page
Winter sowing is an easy, low-cost method to grow native plants from seed that require a process called stratification*. It can be useful for propagating most native perennials/shrubs/vines. I began using this method of propagation last year and had really good results, growing Virgin’s Bower, Clematis virginiana, Zigzag Goldenrod (Solidago flexicaulis), Virginia Mountain Mint (Pycnanthemum virginianum). This type of propagation could be compared to the slogan ‘Set it & Forget it’ campaign for cooking. Basically, you begin in winter – and leave the plants outdoors in the snow until spring. Some questions you might have:
- If you plant in winter, is that now? Yes – From November to the beginning of February should work fine
- Why wouldn’t you just spread seeds on the soil this spring or fall? I’m a little forgetful and might inadvertently plant something else there next spring or walk on the area, compacting the soil. The container gives the plants a protected location.
- Is it really a set-it and forget-it method? Mostly – I did go out and look over the plants a few times in the winter to check that the wind hadn’t blown them over and that squirrels hadn’t upended them, netting over the pots is helpful in preventing this.
- Why wouldn’t I just stratify seeds in the refrigerator and then begin growing the plants outside in the Spring? A good method if you forget to sow outside but using winter sowing, plants naturally ‘harden-off’ and adjust to outdoor growing conditions.
- Where do you get the containers? You need to collect transparent or translucent plastic containers (so that you can create a mini-greenhouse including drainage holes, access to the plants, and venting). Since I don’t use a lot of containers like these I speak to neighbours and friends in order to gather enough of the right container. My containers were a variety of shapes and sizes. You do want to make sure they’re stable outdoors, so if they’re likely to topple over you may want to wedge them in.
- Are there any other advantages? This method allows a gardener to grow a large variety of plants in a somewhat controlled manner – at very little cost.
Final comments: My plants last spring began to grow, what seemed like very late. I thought that they weren’t successful. It was a slow spring last year, but I suggest that you not give up on your seedlings until late spring. In addition, the resulting seedlings are quite small. Some I placed in the ground – and there were no flowers this past season – just vegetative growth; others I just left in the container throughout the entire growing season and planted this fall. I am learning to be more patient and label the location of the plants. It really is a ‘win-win’ way to expand your gardens, add new native plants and further your understanding of horticulture.
*a general term that refers to a range of processes used to simulate natural conditions (typically temperature and moisture) that seeds require before germination can occur
More information: 2 videos on preparing and planting the containers:
There is also a Facebook Group called: ‘Winter Sowers’ that is a community of gardeners using this method to grow a wide variety of plants.