I have a lot seeds that I plan to directly sow in my garden in the spring. But I also have many that are suggested to start growing indoors 2 weeks, or even 10 weeks before the last frost date. So, winter sowing of native perennial seeds is a method I am considering to get a head start on the growing season on my homestead.
A Solution for Limited Space Under Grow Lights
So, I’ve started growing the 10-weekers in pots in my basement under a grow light, but even though I have a good bit of space indoors because I live in the exurbs, it’s still cramped. However, after posting my setup on Bluesky, someone suggested trying a technique called “Winter Sowing”, particularly for native seeds. Winter sowing of native perennial seeds could really help them thrive. So, after looking into it, it seems that winter sowing is mainly just used to start seeds that need to be cold stratified. Instead of cold stratifying the seeds for 60-90 days in a bag in your freezer, you just put them in a covered pot outside. Then, you allow the weather to do its thing to the seeds.
Winter Sowing Seems Like an Extra Step
You might ask the question, “Why not just sow the seeds directly into the ground?” – that’s a great question! And I had the same one. Well, if you plant seeds directly in the ground over the winter, they may be dug up and eaten by wildlife. Additionally, if they’re small seeds that are on the surface, they may be moved to a place where they can’t put down roots (like on top of a rock).
So, the winter sown seeds are protected from wildlife by the cover on the pot. However, the cover should have holes in it to allow airflow and let rain in. It should also allow you to water without having to take off the cover. Many people use clear plastic milk jugs that they make holes in and cut in half horizontally. They use the bottom for soil and tape the top back on.
I’m planning to use roasting pans because my milk jugs aren’t clear. I think I can fit quite a few more seedlings in a small space. This winter sowing of native perennial seeds method seems practical. I’ll update with pics after I sow.
Update 1: Winter Sowing Seems Simple
Update: I used a bunch of roasting pans and it was pretty quick. I made holes in the bottom of the aluminum pans with scissors. Additionally, I melted holes in the clear plastic tops with a soldering iron.
I learned a tip to use potting soil to fill most of the pan. Then use a layer about 0.5″ thick of seed starting soil on top of the potting soil, particularly for small seeds. Seed starting soil is more expensive than potting soil. However, it has a much finer structure (i.e. no wood chips) that the tiny roots of the small seeds can more easily dig through. The choice of soil is crucial in winter sowing of native perennial seeds. I also used some clear plastic strawberry cases that were pretty deep as containers (top right of the pic with the roasting pans).
Native Perennial Plants
So, I sowed some American Black Cherries, American Plums, American Persimmons, Pawpaw, and Red Mulberry seeds which are all native to my area. I got the seeds from seedvilleUSA.com, though I kind of wish I had known about the seed exchange a few months ago. I also sowed some of those seeds directly into the ground in the forest floor. So we’ll see which method has more seedlings survive. I did not do anything to protect the forest-sown seeds from animals. Therefore, I’m not sure if there’s much hope for them, though the Pawpaws seem to spring up all over my neighborhood. So, I suspect at least those will be fine.
We’ll see if this winter sowing of native perennial seeds is effective in a couple of months.
Update 2: You Can Plan a Pretty Picnic, but You Can’t Predict the Weather
I think I may have started my seeds a little too late. I started them at the end of January. It’s now March 18th. I think spring is coming early to Southern Maryland. There haven’t been any days below 32F in the last 10 days, and none are predicted for the next 10 days.
Normally, I’d be ecstatic to have this kind of weather so early so I can start to get some plants outside. However, I’m worried that the winter sown seeds might not have gotten enough cold stratification to germinate. Hopefully, the mid-30s weather will be enough for them to germinate.