Pippi, the problem I've run into with smaller celled containers is drying out so quickly. One of the things I love so much about wintersowing is the ease and lack of babying. I typically don't even have to start watering them till late April or May. I used peat pots for Poppies and Larkspur once, and they required a lot more attention. So, I think it will work, just requires a lot more attention.
