Over winter fails

So this is my 3rd winter having adenium obesum seedlings. I bring them into my cold garage for the winter. Every year they shrivel up and die. Do I need to keep growing them under a light? What am I doing wrong?

This one is under a light just for the photo.

So this is my 3rd winter having adenium obesum seedlings. I bring them into my cold garage for the winter. Every year they shrivel up and die. Do I need to keep growing them under a light? What am I doing wrong?

This one is under a light just for the photo.