Hmmm good question. My seedlings when I had a manageable amount were grown inside on our southfacing window and we keep our temperature at the lowest would be 70s winter time. (Compared to 65 when we Iived up north.)
If my seedlings are over a foot tall or too wide they will not fit the windowsill, they get booted out of the house and stay at the covered porch
Most would keep their leaves, if I keep their dirt moist but not wet.