Rooted Ramblings: What is winter sowing?

Written by Karen E. Smith and Susan Benedict, Portage County Master Gardener Volunteers

What is winter sowing, you ask? Winter sowing is the way many plants perpetuate themselves. They grow from seeds, make flowers, set new seeds, then, in the fall, disperse their new seeds by gravity, wind, water, birds, or small mammals to sprout again, somewhere, next spring. 

Winter sowing is also a late fall through mid-winter, family-friendly activity whereby gardeners of any age sow seeds in containers and leave them outside over winter. Winter sowing works well in your back yard, on a porch or deck, in raised beds, if you have them, in regular garden space; anywhere you can put the containers, so they receive rain and snow and sun, all provided by the natural weather cycles of winter. This treatment causes the seed coat to break down over time and, when the weather warms in the spring, the seeds sprout. The word for this cold, moist treatment, is stratification. For different seed types, stratification times vary from 10 days to 90 or more days.  

Some native perennial flower seeds that require or benefit from stratification include common milkweed, blazing star, gray-headed coneflower, and Ohio spiderwort. Germination Studies for Various Wildflowers. 

Some vegetable crops, such as asparagus, artichokes, kale, lettuce, and peas, as well as some evergreens and other tree or shrub species also require or benefit from stratification. Advanced Techniques to Prepare Seed to Sow. 

Sowing in containers has several advantages: the seeds are protected from birds and rodents over the winter, in the spring, the seedlings are likely to be the plants you expect, and winter sowing is nearly free. Recycled translucent or transparent gallon jugs are the most recommended containers, but any container will do if it allows for some light, drainage, deep enough soil, entry of rain and snow, and protection from birds and rodents. Clear plastic berry containers, under-bed or other totes, 2-litre bottles, and even plastic bags can be used. Numerous sites on the internet and YouTube provide different methods of winter sowing. Visit here for guide on seeds and winter sowing which includes a link to a stratification chart for native-to-Ohio perennial flowers and, for a fact sheet from The Ohio State University with a handy sidebar giving a sowing timeline, visit OSU Winter Sowing. 

For the basic jug method discard the cap, cut the jug around the shoulder, leaving about an inch under the handle uncut to act as a hinge. Punch one to three holes near the cut edges of both the top and bottom, where you will eventually insert twist-ties to hold the halves together. Cut drainage holes in the bottom of each jug. Holes on the bottom will allow excess rain or snow to drain completely, but cutting the drain holes an inch or so up the sides will allow some moisture to accumulate, avoiding the danger of drying out. Fill the jug gently to an inch from the top with one of the many good seed starting soils available. Sprinkle the seeds sparingly. Resist the urge to put all your seeds in one jug. Come spring, when it's time to transplant the seedlings, thickly sown seedlings' delicate roots will be intertwined and difficult to separate. More jugs, with fewer seeds is the key. 

Don’t forget to label each jug! Labels fade over the winter, even if permanent marker is used. To alleviate this problem, make duplicate labels: write the name firmly on two popsicle sticks, using an ink pen; stack the sticks so one label hides the other and insert them in the soil. In the spring, the hidden label should still be legible.  Twist-tie the jug halves together, no lid, put the jugs outside where the rain and snow can water them. Go inside, put your feet up, have a cuppa something, and wait for spring. 

Everyone interested in growing plants from seed, in saving money, in the joy of gardening, in supporting our environment, or who needs to scratch that mid-winter itch of needing a fix of hands-in-the-soil can find winter sowing to be a great activity for the whole family. 

Ohio State University Extension Portage County Master Gardener Volunteer program. As OSU Extension Master Gardener Volunteers, our articles will never endorse specific products or companies. Questions/comments/suggestions/want to find out more/become a PCMGV: 330-296-6432 •  OSU PCMGV web • portco.mgv.oh@gmail.com • FB PCMGV • PCMGV Speaker’s Bureau