Thanks, Barbara -- the info about the "forcing" is really just what I was looking for. I definitely need to bring them inside for the winter, my GH is unheated except for a short time in the spring when i'm starting seedlings (and even those get initially started under lights inside and then moved out to the GH in April); but the shop stays cool and has a good south-facing window, so I think that's my best option.
Just to make sure I understand correctly -- I should just keep on watering (and maybe fertilizing?) and let them follow their own course? Thanks again!