There’s an old-fashioned seed-starting technique that’s getting a lot of attention and I decided to try my hand at it last year. It’s called winter sowing, and it’s basically creating mini greenhouses to start your seeds outdoors during winter.
Winter sowing is low-cost, using repurposed milk jugs and other plastic containers that take the place of an expensive greenhouse or grow lights set up in your home.
Winter sowing takes place outdoors, making it perfect for gardeners who don’t wish to set up grow lights and shelves inside their homes. All of this applied to me: no extra room in the house to set up trays of seedlings, no fancy greenhouse, either. So, last year, I set about buying up seeds and assembling containers for my winter sowing project.
Set up Seeds for Winter Sowing
Like most gardeners, I have a collection of seed packets. I keep mine in a shoe box. To prepare for my winter sowing project, I sorted my seed packets by type and then grouped them by germination times.
The best seeds for winter sowing in my area are the ones that say “start outdoors two to four weeks before last frost date.” These seeds need cold temps to germinate.
(I’m in zone 8A in metro Atlanta and our springs are short. We go from cold, gray 40-degree days in mid-March to 80- and 90-degree days in mid-May. For the plants that can tolerate being transplanted, starting seeds in these mini-greenhouses makes sense.)
Far and away, my biggest success from the first year was nasturtiums. I also had excellent germination with lupines and snapdragons, but not much success in transplanting to the garden, mostly due to the above mentioned obscenely hot temps with a lack of rainfall in late spring.
I’m giving winter sowing another go this year, and trying to work smarter, not harder. I’m writing this the first week in March and I’ve sown:
- Borage
- Echinacea
- Plains coreopsis
- Tall coreopsis
- Blanketflower (gaillardia)
- Ornamental millet
- Blue sedge grass
- Snapdragons
In a few weeks, I’ll sow marigolds and basil for planting in containers and my keyhole garden.
How to Winter Sow Seeds Bin Method
I use clear plastic bins that I bought at Wal-Mart. Make sure you get the tall ones to allow for the seedlings to grow. This can be a big investment the first year, but you’ll be able to use the bins for seed starting in subsequent years.
For the containers, I use recycled nursery containers from previous years. I eat a lot of yogurt and save the one-quart containers for this project. I poke holes in the bottoms of the containers using a utility knife. You can also use a drill. No matter the container you use, make sure to have drainage holes.
For soil, I use good quality potting mix. You can mix your own from garden soil and compost, but make sure you have a light and fluffy soil that’s moisture-retentive and well-draining.
For labelling, I use blue painter’s tape and a Sharpie. You can use craft sticks or bits and bobs of repurposed plastic, but painter’s tape works for me.
Steps to Winter Sowing Bin Method
Step 1. Drill holes in the top and bottom of the bin. I use my cordless drill and it takes very little time. Make sure you do this outside and follow all safety precautions, including wearing eye protection.
Step 2. Select the seed you’ll be sowing and write out your labels. Make enough labels for the number of containers you plant to fill. I sow the seeds pretty heavily in each container, figuring I’ll either thin the seedlings or break them apart when I plant (according to the Winter Sowing FB group I learned this from, this is the “hunk o’seed” method).
Step 3. Place label on containers and fill containers with soil, leaving a half-inch space near the top.
Step 4. Place seeds over the top of soil. Cover with another handful of soil, lightly pressing with your hands.
Step 5. Place containers in bin. When bin is full, gently water the pots and place lid on top.
Step 6. Place container in a sunny area. Check every few days to make sure the plants are getting enough moisture.
As temperatures warm in spring, you may need to move the bins to a shady area so they don’t overheat. When that happened, I decided it was time to plant my garden.
When It’s Time to Plant
Seedlings need to have at least two sets of true leaves before they’re ready to be planted in the garden. I let mine get pretty overgrown before setting them out. If there’s no danger of frost, you can just open up the bins and let the plants soak up all the sunshine and moisture until you’re ready to put them in the garden.
I’ll keep you updated as the season progresses with my winter sowing project. In the meantime, have you tried winter sowing? What are your successes and what have you learned from the process? I’d love to hear your comments.
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