By Pat Cook, Master Gardener, SCMG
Winter sowing is a method of starting seeds outdoors in winter. The process relies on sun, snow and rain and produces strong, sturdy plants. Here’s how easy it is:
Step #1 – You will need lots of clear juice jugs, duct tape, a sharp utility knife, permanent marker, soil and seeds.
Step #2 – Drill holes in bottom of jugs to allow for drainage. Cut the jug along three sides at least 4 inches up from the bottom. Leave one side uncut to act as a hinge.
Step #3 – Fill the bottom half of the jug with at least 4 inches of pre-moistened potting mix (to allow for root growth). The mix should be moist but not wet. Sow the seeds on the soil surface. Cover with more soil.
Step #4 – After you have planted the seeds, tape the top and bottom of the jug together using duct tape. Label the container with permanent marker on the tape.
Step #5 – Your jugs are ready for the great outdoors—even if it’s snowing! The plastic container acts like a greenhouse, keeping the seeds warm (but not too warm) and moist. Place them where they’ll get light and rain or snow (make sure the cap is off the jug), but they won’t blow away. Snuggling them close together helps provide some stability.
As the weather warms up, flip back the tops on nice days but close them again at night. When evening temperatures stay above freezing you can leave the tops off permanently. You’ll need to keep a close eye on the jugs so the potting mix doesn’t dry out.
The containers used in winter sowing act as mini greenhouses, allowing the seeds to experience the chill of winter in a controlled environment. When the conditions are right and the temperature warms up, the seeds germinate and start to grow on their own. Seedlings grown this way are hardier than those grown indoors under grow lights.
Choose seeds that are hardy. Seeds of tropical and tender plants will die in the cold. Some good choices for winter sowing include:
Flowers: Alyssum, Butterfly Weed, Calendula, Coreopsis, Cosmos, Foxgloves, Hollyhocks, Petunias
Vegetables: Beets, Broccoli, Cabbage, Chard, Carrots, Kale,