I'd leave them dry they are not going to be doing any growing right now and if the compost is damp they could possibly start to rot.

Alstroemerias, however, don't stay hydrated very well when bare root. They will, however, grow under cool conditions, as long as they are not freezing, and they have enough light. They grow in the winter in their native Peru and Chile, and we grow them as winter annuals here, where we get light frost. A minimally heated greenhouse or conservatory may be the best place for them, since they came at the wrong time of year for your climate.