Some flowers prefer winter sowing. (Yes, in snowy winter!) Many flower varieties need an extended period of cold to germinate; this is called stratification. Learn how to winter-sow this year to jump-start a beautiful flower garden (and do it for pennies).
What Is Winter Sowing?
Those of us in cold climates don’t usually think of January and February as times to be planting seeds outside, however, in the case of many perennials and hardy annuals, this is definitely the time to do it! Many flowers like a period of cold, wet weather to germinate.
(Wait until late winter or early spring to plant tender annuals.)
Take a look at nature: Our favorite native plants, annuals, biennials, and perennials are laden with seeds, dropping them where they will sprout next spring. Follow nature’s lead and take advantage of this process to add new plants to your landscape or just increase the numbers of ones you already grow.
Don’t worry; waxes, hormones, and heavy seed coats keep the seeds from sprouting at the wrong time. The alternate freezing and thawing in cold moist soil breaks these down so the seeds are ready to grow come spring!
Add some fancy double columbines to your garden!
Which Flower Seeds Are Good for Winter Sowing?
Any plant that is “hardy” in your zone is fine to plant in winter. These flowers have no problem with snow or frost and, in fact, need the cold. Here are some of my favorite flower seeds for winter sowing in January or February.
Buddleja (butterfly bush)
How to Winter Sow Flowers
When it comes to winter sowing seeds, there are several ways to do it.
In the Fall
Just let nature do the work and let the seeds drop. Discover 20 self-sowing flowers. Or, scatter seeds where you would like them to grow. This works best for plants that dislike transplanting including poppies, lupine, larkspur, bachelor buttons, and lunaria. I have also had great luck scattering poppy seeds over the snow in late winter.
Or, after a killing frost, sow the seeds outside in a nursery bed where you can have more control of the surroundings and keep an eye on them easily. Once they are up and growing well, next spring you can move them to their new locations. I prefer this to scattering, especially when I have purchased the seeds rather than collected them. Don’t cover small seeds, just press them into the surface of the soil—well-drained, weed-free soil. Over-sow by about 20%.
If space in your garden is at a premium, you can start the seeds in pots outdoors. Just be sure to use pots that won’t crack over the winter. Again, do this after a killing frost but before the soil freezes solid.
In the Winter
If you prefer starting the seeds indoors, you can trick them into sprouting by giving them a period of moist cold in the fridge. You can either plant the seeds and place the containers in a plastic bag and put them in the fridge or other cold spot where they will stay below 45 degrees for at least 2 months. If you don’t want pots of dirt in the fridge just place the seeds in plastic bags with a bit of moist soil or vermiculite. Don’t place dry seeds in the fridge or freezer to stratify them. Moisture and cold are the key elements.
The classic winter-sowing method is to simply seed hardy perennials and annuals outside in recycled milk jugs or water jugs in January and February and place outside to let nature do its thing. No need for grow lights, seed-starting kits, or anything else! No worries about your seedlings growing spindly on the windowsill with weak winter light.
Use clear, one-gallon milk or water jugs.
Cut across the width of a clear one-gallon jug just below the handle so the bottom becomes a tray. Try not to cut all the way through so you leave an inch at the back and then the top of the jug is still attached and becomes a hinge.
Punch out some drainage holes in the bottom and a few holes in the top for ventilation.
Add 2 to 3 inches of potting soil to the bottom, moisten, sow seeds, and firm the soil.
Cover the lid of the jug and tape it to the bottom. Now, put the jugs outside! Make sure they’re in the sun but sheltered from the wind.
Let seasonal precipitation and low temps do their magic until spring.
In early spring, look for seedlings. Open the jug’s tops and gently check the soil. If it’s dry, moisten gently. Close the tops. As the days get warmer, open the tops but close at night.
Joe-Pye weed is a lovely fall-blossoming plant that butterflies love. Its seeds need a period of cold to germinate.
What’s great about winter-sowing is that you don’t waste time or money trying to grow lanky seedlings on windowsills. You’ll have strong, sturdy starts and it’s really easy because nature does most of the work!
Planting a mini-nursery of perennials from seed is a budget-friendly way to add plants to your garden, especially if you have collected the seeds for free!
The poppy seeds I have scattered over the snow have always germinated best for me.