It was only 9 degrees here this morning, we got snow before the ground froze last fall that stayed so many plants were up when the snow went. We had a few warm days to get the snow melted and things growing and then it turned nasty cold. The alliums are black along with some of the tulips. The daylilies that had started to come up don't look good. It's suppose to be cold again tonight and then start warming up a little to at least above freezing in the day.
Caroline, I have the same problem you do, all my light shelves are full and all the surfaces by windows are getting the overflow. When it is to cold to get outside I just start more plants.