If I were you I'd probably do that if you don't want to plant them in the ground.
Mary

Thanks Mary...most of these seedlings are the ones I got from you, and they are doing just great. Not a single one died! I will plant them in their new bed outside in the spring.

Cindy

If your seedlings were potted up for some time i would advise you to leave them outsde and not weeken them by bringen them under cover the hare realy hardy plants.I have around 1000 plants i grow from seeds last year,the wil be in there second season next summer,end i hope for some good coulors the are "Helleborus Atropurpurea.
Regards and good luck

I totally agree with geedo.

In your zone, I'd leave them outside under a pine tree, with lots of mulch (pinestraw) pulled up around the base of the pots to protect the roots from any cold and drying winds.