Have you heard of it? It’s an old practice that seems to have gotten more popular the last few years with people sharing their process on social media. It’s a cheap, easy, way to grow plants from seed. You don’t need very much for supplies to give this technique a try.
Some types of seeds require stratification (exposing seeds to cold/moist conditions) for germination. Many perennials, flowers (like poppy), nut seeds, cold hardy vegetables (onions, kale, some greens) benefit from stratification and perform well with winter sowing. Even after repeat freezing and thawing, they know when it’s time to “wake up” and start growing. This technique doesn’t work well for all types of seeds though. Heat-loving crops like peppers and tomatoes do not work as well for this process because they’re super slow to germinate and then slow growing, and they would suffer from cold temperatures and frosts. The cold hardy seeds won’t mind those same cold and frosty conditions.
Of course, winter sowing also includes directly sowing seeds in the outdoor garden, but to keep a closer eye on them and keep them sorted from the weeds also germinating in the spring, plastic containers (4 L water jug split open around the middle, big plastic lettuce clam-shell etc.) are a popular choice for winter sowing containers. Whatever you choose for a container, it needs drainage and air flow, so poke holes in the bottom of the plastic container before filling with moist seed starting soil. Scatter seeds on top of the soil and then cover them with some more soil. Close the containers back up, and place them outside while it’s still cold.
Winter Sowing is done during the cold winter months (December to March here). I usually start seeds by winter sowing in February when it’s still too early to start most seeds indoors, but I’m getting the itch to start gardening. I use plastic water jugs. I tape them back up where I’ve split them open to plant and keep the lid on them until the seeds start to germinate. I tuck the just in a protected (but sunny) corner beside the chicken house where they won’t blow away and keep peaking once the weather starts to warm up. Once they start growing, I open up the taped section or take off the lid to allow for better airflow and keep them from getting too warm.
Here are a few photos of my winter sowing containers and seedlings from the past couple winters.