Someone from your zone can probably give you better or more advice on this, but if I were you, I wouldn't chance them in pots over winter that far north. I'd go ahead and plant them in the ground and if you want to mulch them there, you can. You should get plenty of snow cover to insulate them, I'm thinking.
Hopefully, someone from your zone will tell you what they think too.
Good Luck,
Jan

Plant them in the ground and mulch at least their first winter.Less chance of losing any.

Betsy

If you had them in pots, you could always move them into a cold frame or some other kind of shelter. That said - I put my seedlings into the ground and left them last fall. I think they're still alive. Its been a on and off cold winter , without much snow in my zone 6. I plan to pot my 100+ seedlings in 1 gall pots this spring. I'm interested also what to do with them in spring, will potting them slow the bloom time any?

Even in zone 5 I don't expect much to winter over in pots. The root zone is much more protected if underground. Subzero temps are just too much for the roots of most plants.

Yes, you can use coldframes or other protection for potted plants but even then I would mulch the inside of the coldframe and keep several inches of mulch or other insulation between the pots and the outside edges of the frame.

It's easier to just put them in the ground and mulch over the top.

tweetypie and berrytea4me have my vote.

We put them in the ground when mother nature let us. Usually mid April in our zone. If they get 3 months of growth in the ground they will be fine; unless they aren't hardy enough to make it through your winters. Atleast that's been our experience.

Here is a link that might be useful: Our garden and seedlings

This is my first try at Winter Sowing and right now I have 50 seed crosses in clear 16oz. cups (3-5 seeds to a cup) sitting outside frozen solid and covered with about 3' of snow! I put drainage holes in the bottoms with a soldering iron and the tops of the cups are covered with a sandwich baggie that also has vent holes.

(I also have about 50 milk jugs out there planted with all sorts of perennials and will add the annuals in a few more weeks.) I have been watching the WS forum for several years now, so jumped in with both feet. Will let you know how it turns out.

If you do decide on pots, I recommend using 2 gal minimum per plant for a decent sized blooming fan. 1 gallon is just not large enough.

Carmen wrote This is my first try at Winter Sowing and right now I have 50 seed crosses in clear 16oz. cups (3-5 seeds to a cup) sitting outside frozen solid and covered with about 3' of snow!

Question I have never heard of doing this with daylily seeds wouldn't they all be frozen to mush and not viable? I would think the cups would leave the seeds totally unprotected.

Flowergardener, this is the first year I have attempted this. I figure that if daylilies seed themselves in the garden (and they do) why can't they stand the freeze/thaw periods? Please understand that I sowed my seeds, but I kept some of the best just in case this doesn't work out. The people on the Winter Sowing Forum swear by this method but I don't know how many have tried it with daylily seeds.

I will let you all know what the results are!

Here is a link that might be useful: Winter Sowing

Carmen I have heard if winter sowing before just not for daylily seed. I think when daylilies sow themselves in the garden they may have some protection from the soil, mulch and snow. I have never had seedlings pop up from seeds that I may have missed in my garden. I will be interested in hearing of your results.

Though I'm in a much warmer zone, last year I winter sowed daylily seeds and they all came up. We got down into the mid 20's a couple of times and only warmed up into the high 30's during those days. So I know the daylily containers had to be frozen.
So it can be done. Possibly in colder zones too. It will be intresting to see how your's do Carmen.

Joy

I've got a few winter sown also, just as an experiment. Of course I'm in zone 8 and don't know about the colder zones. I'll also let ya'll know if these germinate, and how they do.
Jan