A few years ago, I successfully winter sowed some penstemon, California poppies, and columbines by sprinkling the seed on potting soil in clay pots, and then covering the seed with a layer of fine gravel. I prepared the pots in late December and then put them outside on our front porch, up next to the short brick wall on the east side of the porch. They got a good dose of morning sun every day (Denver has lots of sunshine, even in winter), and when it snowed, they ended up with anywhere from a light dusting of snow to a few inches of snow that melted off in a couple of days. I didn't cover the pots with anything to help hold in moisture and only watered them two or three times if they were starting to look particularly dry.
Has anyone else ever tried this method of winter sowing, and if yes, was it successful? I've been away from gardening for a couple of years now but getting back into it again and am particularly looking forward to trying the clay pots with gravel again this winter to see if will work again. I'm also considering trying some of the other types of containers (e.g., milk jugs and whatever else I can lay my hands on) that will provide a bit more of a greenhouse effect and will put them in the same semi-sheltered location on the front porch. Because it is not as open to the elements as just plunking everything in the backyard, I'm sure I'll have to provide a drink now and then, especially if we have another dry Denver winter. I'm kind of concerned about being too zealous with the watering though. How dry do you all usually let things get in your containers, especially before the seed has germinated?