Winter Sowing: Head Start on Spring

By Sarah Edmonds

Recycled plastic jugs can be used as outdoor containers for starting seeds over the winter. Photo by by Tina Gustafson

The winter season is one of those down times for gardeners.  Snow is on the ground, but it is too early to start seeds indoors.  Yet Tina Gustafson, founder of Elevated Gardening, discovered something to do while it is cold and the daylight hours are short—winter sowing, which she learned about on Facebook!  One of the administrators of the “Winter Sowers—The Original” Facebook group is Trudi Greissle Davidoff, a New York gardener who developed and popularized winter sowing beginning in the late 1990’s.  It involves sowing seeds outdoors during the winter in recycled containers.  Often people use old milk jugs, but plastic bags and other plastic containers can be used as well.  

Gustafson says, “Many of our native flower seeds need cold stratification to break their dormancy so they can germinate in the spring.  The easiest way to do that is to put the seeds directly outside instead of in the refrigerator.”  She’s had success winter sowing milkweed, penstemons, asparagus, rhubarb, and herbs, yet annuals such as marigolds, zinnias, chard, lettuce and many others can be grown this way.  People in cold climates from Chicago to Michigan also claim success in winter sowing tomatoes!

Want to try it?  Here’s Gustafson’s method.

“Get your jug and drill a bunch of holes in the bottom for drainage. Then cut it almost all the way around, but leave a hinge where the handle is.  Use pre-moistened, high-quality potting soil and take out large woody material, because it will hinder germination. Fill your jug with 4-6 inches of your soil. Then sprinkle your seeds on top.  For small seeds, press them into the soil.  With bigger seeds, put a little soil on top and moisten it again.   Make a label for it and put it inside of the jug.  The sun can make an outside label disappear!  Then close the hinge and tape around the cut.  Do not put the original screw top lid of the jug back on, because rain and snow should be able to get in there.”  

“You do need to monitor moisture.  If you let the soil dry out at all, then your seeds are going to die.  These are essentially mini greenhouses for plants.  With this method, you are growing the strongest, most resilient plants.  Once the seedlings get two sets of true leaves, or reach about two inches in height, you can transplant them into your garden.”

Gustafson says starting seeds using the winter sowing method should make your life easier.  Just think—no grow lights or heat mats and no hardening off period.  The only thing you do need to be concerned about is keeping the seeds moist.  Water them every 3-4 weeks if there is no rain or snow. Once the sun gets stronger in the spring, the jugs may need to be moved to a shadier spot, but when you first sow them in the winter, usually putting them in the sunniest spot you have is best—as long as they aren’t on a walkway or an area where they’ll get disturbed by snow shoveling or dogs looking for something interesting to play with.  When you are ready to transplant, untape the jugs and push the plants and soil up from the bottom.  Use a hori hori knife to easily cut the seedlings and root systems apart.

After being exposed to winter conditions, especially cold temperatures, for a few months, early-spring germinating plants like these asparagus can be removed from the plastic containers and planted out.  Photos by Tina Gustafson

Gustafson also sells locally adapted seeds and plants through her small family business. “I’m passionate about finding and stewarding varieties that grow well in Flagstaff. I ship my seeds all over the US, but also do markets here in town.  I teach workshops on all kinds of gardening topics, like high altitude gardening, seed starting, garden planning, composting, vermicompost, saving seeds-- pretty much whatever people are interested in.  I also do consultations in people’s gardens to assess their growing environments and help them grow their own food at high altitude.”  To get in touch with Gustafson, go to https://www.elevated-gardening.com.

Sarah Edmonds earned a Home Horticulture Certificate from the University of Arizona Cooperative Extension in 2024. Gardening Etcetera is written for the community by certified Master Gardeners of the University of Arizona's Coconino County Cooperative Extension Master Gardener Program. To learn more visit https://extension.arizona.edu/programs/coconino-county-master-gardener.