Experiments in Winter Sowing, Part 1
Growing flowers in the dead of winter is a leap of faith. Will they germinate? Will they freeze? Is this a terrible idea?! But despite these fears—I am still heading into the new year (my first as a flower farmer) knowing that action is better than inaction. And action feels especially liberating in 2022, after spending the entirety of 2021 in planning mode while trying to find a new home in this crazy housing market.
I’m embracing the “you won’t know until you try it” attitude this year. I need to experiment and learn what flowers will thrive in the heavy clay soil we have on our south facing slope in the mountains of western North Carolina (zone 6b). I expect some—okay many—failures along the way, but I’m eager to learn and ready to get my hands dirty.
The first thing I’m experimenting with is sowing flowers during the dead of winter. This should—theoretically—make for a larger variety of blooms, available for harvest sooner. This short list below are some of the flowers I’m trying out. They define the saying “what doesn’t kill you makes you stronger” since cold temps make them tougher so they thrive once spring arrives.
Lupine
Photo by Irina Iriser from Pexels
This flower is a labor of love. First, the seeds require a period of cold stratification that simulates their natural environment. This can be done by storing your seeds in the fridge for roughly six weeks. Before sowing, each seed’s tough exterior must be carefully and tediously nicked before soaking in warm water for 2–3 days. If you skip this step you will suffer from poor germination.
For us, it was quite tricky to nick only the exterior without cutting the entire seed in half. After soaking, the seeds were sown in a 72-count tray, covered with ⅛” of soil and a clear germination dome. I placed the tray under grow lights in our greenhouse without using a heat mat, since the soil needs to be cool, (roughly 55-70º) for germination. The seed packet said they can take anywhere from 10–75 days to germinate. One already germinated in less than 10 days. This seedling is clearly an overachiever as I’m still waiting for the others to follow suit.
Delphinium & Larkspur
Photo by Albina White from Pexels
While both flowers share similar looking blooms, they are in fact two separate flowers even though they are a part of the same family: Ranunculaceae. Larkspur is an annual while Delphinium are typically grown as short-lived perennials—with 3-4 seasons of blooms. Delphinium flowers grow densely on tall spikes and the individual blooms are larger than Larkspur. To me, Larkspur looks like a wilder, more natural cousin of Delphinium—not as dense but more delicate and just as beautiful nonetheless.
Larkspur and Delphinium are grown the same. Both require a period of cold stratification. We placed our seeds in the fridge for about a month prior to sowing. Then, we sowed them in a 72-count tray and kept them covered so they are left in complete darkness until germination. No supplemental heat was provided. They are in our hoop house which currently gets about 25–30ºF at night and 60–75ºF during the day. So far, after about 20 days, almost all of the Larkspur have germinated—eek! Hoping the Delphinium will follow shortly behind. Both will be planted out as soon as the soil can be worked in the Spring.
Sweet Pea
Photo by Алекке Блажин from Pexels
These tall fragrant climbers are quite cold hardy. I got the idea to sow and overwinter them from the Let's Grow Girls Podcast across the pond. I sowed three 72-count trays, planting them fairly deep—about ½” inch. Some people pre-soak their seeds, but many report success just giving them “a good drink” as Monty Don would say—so we watered them heavily instead.
After two weeks in the hoop house almost all germinated and their first true leaves have appeared. When they get to be about 6-8” tall, we will pinch them back to promote bushier growth (and therefore, more flowers). I’m actually worried just how fast they are growing! Hoping the return of colder winters will slow down their growth, otherwise I might wait until February next season to sow them.
Columbine
Photo by Skyler Ewing from Pexels
These plants also require a period of cold stratification (are you noticing a theme here?) I put my Columbine seeds in the fridge for about a month before I planted them. Some suggest sowing the seeds then putting the entire tray in the fridge for up to a month—if only I had room for that! I love my flowers but room for food will always be more important. Columbine requires light to germinate so I made sure not to cover the seeds. I pressed them gently into the soil of a 72-count tray, covered them with a clear germination dome and set them under grow lights. A few have already germinated after about two weeks—though it might take another two for them all to germinate.
Columbines, like Delphinium, are also considered a short-lived perennial—meaning they will bloom for 3-4 seasons. I love their unique, intricate blooms and I was surprised they have a vase life of 6-8 days since they seem so delicate.
Lisianthus
Photo by Алекке Блажин from Pexels
They say patience is a virtue and this flower proves it—taking up to six months to bloom. And though I wouldn’t say it loves the cold, it’s still fairly hardy when planted out—even though it likes to stay around 72º for germination. But since they take so long to bloom (150 days), you basically have to sow them in the winter to get summer blooms. Good things come to those who wait however, since Lisianthus is one of the most beautiful cut flowers and has a long vase life of up to three weeks.
Notoriously difficult to start with extremely tiny seeds, they need light to germinate and need kept in a temperature controlled environment. One of my biggest struggles so far with this flower has been maintaining a consistent temperature in our new greenhouse. That might explain while I only have about a 60% germination rate so far. I am hopeful the second tray will germinate better and I have plans for improvements to better control the temperature in the greenhouse.
Check back in spring for part two of this blog for updates on how my winter sowing experiment went.