I would welcome your advice. I have daylily seedlings that are between 2 and 6 inches tall, and have 2 or 3 leaves. I am running out of room for them in the house, so I was thinking of putting them on a shelf in the garage where the temp is just above freezing--maybe between 34 and 40 degrees. The garage is attached, and the shelf is on the opposite end from the door. Would that spot be way to cold for them to survive and thrive?

Where do you live? Will those temperatures be rising or are you still in danger of some cold stuff.

I don't think they would die if they don't dry out too much, but growth may be slowed. Will they have some lights that will also generate a bit of heat?

I've had seedlings that were just a couple inches high survive being left outside all winter. Of course those went dormant.

I have some in a room that stays around 50°F. However, they are in
a south-facing window. These grow much slower than the ones
upstairs. Do you have a window in the garage to give them some
light. I don't think they would do very well without some degree of a light source.

Just remembered:
I did once keep a potted proliferation in the unheated garage without much
light all winter, and it survived and grew a bit. Haven't tried that with seedlings though.
You might experiment with a few for a couple of weeks to see how they
respond. Sometimes these little fellas can surprise us.