Winter sowing is something that I am just discovering. What fun> Is it possible to make it work in Zone 4? Where would I put containers, still dealing with temps in the single digits at night. Any info would be helpful. This sounds like fun, anxious to try it. Thanks
Zone 4 should work just fine... hardy seeds don't care about cold temperatures; when it warms up in spring, they'll sprout, just as if the plant had self-sowed by dropping seeds outside the previous year.
I'd try to find a slightly protected spot, so your containers don't blow around. Avoiding afternoon sun is also good, because your seedlings can cook otherwise on a warm spring day.
Click the links in the article for my other articles on winter sowing, and you'll find some additional information. I also hope you'll consider subscribing... Discussions on the winter sowing forum are very active at this time of year, and there's a lot of great information being shared there.
My columbines have done a bit of self-sowing among my irises, also... and even if a columbine starts growing pretty much right on top of an iris, it doesn't seem to be a problem for the iris rhizome (still, move it a bit if you spot it growing so close). So if you've got a lot of columbine seed, just toss it around "out there!" You're going to enjoy the combination. :-)