I wouldn't keep them out 24/7 until nighttime temps are at least in the high 40's, especially seedlings and newly rooted cuttings. Mature plants would fare alright with lows around 40 but won't start putting on much growth until it warms up at night.

I agree with Karyn. The only ones I wouldn't worry about at temperatures that low are Sanguinea, Arborea, and Vulcanicola.

Thank you so much for the info...I really was not sure at what temp they could handle..Still unsure about the soil too..Wi's ground freezes every winter and it takes a while to dethaw...I will just be patient and wait till beggining of june to plant out..They are really growing now and taking up space...LOL..:) Thank you once again! Barb

I am in the same boat as you rosepedal, I can't put mine out until late may/early june, but they are wanting to put on a growth spurt now and I would love to be able to get them outside and have clean windowsills again, lol.
Shawn

I hear Shawn..LOL on the windowsills...You are growing quite a few seedlings too...You must have a lot of windows :)

Karyn great answer and Barb good question about the warmth of the soil. Never thought about THAT

Lucy

I had my brugs outside yesterday and got whisked away unexpectedly, and by the time I got home to move them back in it was about 38 out. I inspected everyone this morning and they're totally chill (pardon the pun), no signs of the slightest damage. wouldn't I be able to tell by the next day, or will any damage take longer to become apparent?

this includes the huge plants from barry last fall, my cuttings, and little baby plants - literally, everything. I'm actually surprised that everyone did so well :P

Ria

They can take more cold when they are hardened off in the fall. Meaning let stay outdoors as the temps gradually get colder. The coldest I had them without damage this winter was 29 F with a sheet over them and 32 without any sheet. I think other factors can play into that like microclimate, humidity, how many consecutive hours at those temps they are exposed to, etc.
Once I got under 27 they got bad top damage and stem damage on seedpods even with protection.
Once it hit around 24-25F the stems were toast even on the big ones and even with protection like cardboard around the stems and frost cloth etc.

If I were bringing brugs from a warmer area to a colder area like now in the spring, then I would prob bring them out when night temps are in the 40's like karyn said. They are more tender now and have to get used to it.