Garden Plants below Freezing

Over the course of the summers I bought/was given/rescued a lot of new plants all of which were meant to be hardy and be able to cope with temperatures under freezing. I've lot 3 already. I moved as many as I could into the spare bedroom and main bedroom window sills. several more outside are looking dodgy and I think I'm going to end up loosing all the new ones. I don't know as I only plant hardy plants and yet they are dying.

Try and move them nearer the house, that’ll give them a little protection rather than the expense of buying a greenhouse and heating it.