The phrase Winter Sowing is attributed to Trudi Davidoff, a resourceful gardener who had more seeds than indoor space. Ms. Davidoff sows seeds in covered containers and then moves the containers outdoors. The containers act a mini greenhouses, allowing the seeds to experience the chill of winter in a controlled environment. When the temperature warms enough, the seeds germinate and start to grow on their own. By the time the soil in the planting beds has warmed, the seedlings are ready to transplant out. This may all sound like common sense, but it took Ms. Davidoff to call it to our attention. The concept has caught on, thanks in part to her website WinterSown.org, and in 2006 the USDA added the term to the National Agricultural Library Thesaurus.
Over the years, Davidoff has refined the technique and offers many tips on the likes and dislikes of specific plants. However sowing seeds in the fall or winter is an old technique used worldwide. You may have tried it yourself, in the vegetable garden, sowing spinach and corn salad in the late fall for harvesting soon after the snow melts. Any gardener who has ever cursed an effusive self-seeding plant knows that some seeds do very, very well when left outside in the cold, to germinate. Starting them in enclosed containers simply gets them going a bit sooner in the spring.
If you'd like to try winter sowing, here are some tips I would suggest:
- Check out Davidoff's site, WinterSown.org. You'll learn from her experience, as well as her advice.
- Choose seeds that are hardy. Seeds of tropical and tender plants will die in the cold. Some good choices for your first efforts at winter sowing include:
- You can either direct seed or start seed in containers, to be transplanted later.
- If using containers, make sure you have drainage holes at the bottom and air vents in the top. Keep the vents small, to begin with, and widen them as the weather warms in spring. Container Gardening for You has a great step-by-step using open water jugs.
- Use at least 2–3 inches of potting mix, preferably 3–5 inches.
- Sow more seeds than you think you'll need, but don't sow too thickly or the seedlings will crowd each other out, when they begin to grow.
- Label your containers.
- Many self-seeders can be sown in the fall, for early spring germination or in early spring, for a later bloom. Start them at staggered times for a longer season.
- Expect to lose a few, but be warned that Winter Sowing is addictive.