I need an opinion please....

My 3/4" tall, two week old sprouts......do they prefer 45-50 degree outside temps under "daylight" cfls or inside my house with 78 degree temp but in the pitch black of night?

This is for about 12 hours daily (from 7:00pm until 7:00am)

The other 12 hours, they are in sun and some shade.

Thanks, all.