Winter Sowing

I apologize if this had been thoroughly discussed, but I can't seem to find anything on the topic.
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I have seen lately on YouTube several people sowing seeds in plastic jugs .
Does anyone have experience with this in cold climates? Zone 4b-5 specifically
Or simply any tricks?
Thanks

Hello Tessa.  We start seeds in many things from plastic containers to homemade paper containers.  The most important thing for us is getting the temperature up to make them germinate.  Here are a few threads where people are talking about starting.

Beautiful beginnings
https://permies.com/t/173327/#1360497

toiletpaper seed starter
https://permies.com/t/173556/#1362389

Seed starting... soil balls?
https://permies.com/t/162643/#1274640

I haven't tried winter sowing yet but I'm also intrigued by it. I know of a lot of people doing it in the Spokane, WA area and while it's not quite as cold as where you are, they have tons of success. I think most of them stick to cold weather crops, and still start tomatoes and peppers inside. They're getting information from the Wintersown.org Website (which isn't currently working for me oddly enough) and from the Winter Sowers group on Facebook.

I just never seem to have enough plastic containers to do it at any scale. I'll have to ask neighbors and coworkers to save milk jugs for me. If I can skip hardening off the early spring plants that would be worth it to me!

My climate is warmer (zone 7b), but I've winter sown for a few years. It's the only way I can get some herb seeds to sprout, especially perennials or those that need stratification. For longer season annuals like peppers, I haven't had as much success or benefits. But I can't have an indoor setup for health reasons (it aggravates mold-related symptoms), so I rely on winter showing for anything that I don't want to direct sow. I'm not good at separating plants without destroying too many roots, though, so I prefer to use smaller jugs and fewer seeds per jug than what the big winter sowing proponents suggest.

I asked a daycare for their jugs, as they go through a lot of juice containers.

Tessa, that is a method I have seen people recommend for milkweed seeds.

This method would work for any seeds that need cold stratification. This is similar to the suggestion of sowing wildflower seeds in October.

By using milk jugs you can control the amount of water that the seeds get, how much sun, etc.

Milk jugs are not require just add a little help, etc.

I'm in zone 5a in far northern Wisconsin. (When I lived 80 miles west of here in northern MN, that was zone 4.) This is my second year winter sowing flower seeds that need moist cold stratification. Last year, my seeds germinated, but my seedlings died because I let them dry out in the sun. I misunderstood the point of the enclosed container such as the milk jug. I thought it was for the greenhouse effect, so I just used the bottom of milk jugs (as well as all kinds of random reused containers) and put them in my greenhouse once spring warmed up. The enclosed container retains moisture! Silly. So this year I'm using milk jugs with the top half taped back in place, as well as various quart and gallon containers with lids. I prioritized clear containers for seeds that require light to germinate, and put others in the opaque containers. We'll see how it goes!

I have not done any winter sowing of veggie seeds. I mean, I start them indoors because many of them need warmth to germinate, including overnight. Maybe it works to get cool weather crops started a little early, but in that case, it doesn't seem different from direct sowing them under cover. I'm interested to learn more!

Another benefit for me with winter sowing vs direct seeding with cloches is that I don't lose the seeds. Ants or other bugs tend to move, devour, or build mounds over certain seeds. Winter sowing protects them.

I tried it last year with mixed results.
I never watered, and I think that was an issue.
I will probably sub irrigate by dipping them in a tray.
The bottles protect from the cold but also from heavy rain and animals.