I've used the egg carton for indoor sowing but found it wasn't deep enough and the roots had nowhere to grow. Ended up with tiny weak seedlings compared to the same seed in larger 3 inch peat pots.

I've tried the egg carton inside, and had the same results as beachgrub. Also, since my light set up is in the basement, I had a huge issue with mold. And after only a short while, they absorbed so much moisture that they began to fall apart when I tried to move them. I had to put them on a board to get them outside. Since they would be likely to get very wet during the spring thaw if outside, this might be a problem. If you're going to try it, I would suggest putting something under them to allow for you to move them without having them fall apart.

Hope this helps :-)

And such a small amount of soil dries too fast, especially in a warm zone. You'll be happier with your results if you use bigger, deeper containers with at least 3" of soil.

Karen

Ditto what Karen said.

Much, much too small, too shallow for winter sowing.

too shallow.

Thanks everybody! It's nice getting so much quick useful feedback. I appreciate it!