What will do well in unheated GH?

Last year I made the costly mistake of keeping my PVC-and-UV-rated plastic sheeting GH heated all winter. Not again.

This year, I'll be doing a few things to make it more energy efficient, namely:
1. a black-painted "rug" of carpet padding (that concrete it sets on gets mighty cold!); and
2. a second layer of plastic with a small fan running to inflate the space in between the layers.

But even still, I know it's going to get pretty cold until I start heating it, probably around late February/mid-March (when I'm ready to pot up the tomato and pepper seedlings, and need the room.)

In the meantime, I'd like to take advantage of the benches within this protected space, even though it's not heated. So what will do well in there from October-February? It faces south, with one wall getting a nice blast of western sun all afternoon.

Namely, can I start perennials in there now? Or would my seeds be better served if I sowed them outdoors in midwinter?

And what about my more tender bulbs, like the rain lilies and agapanthus? Can I set them in this unheated space, or should I place them in the crawlspace for the winter? (Last year, there was no question - they stayed warm all winter in the GH.)

And what about my water lettuce and water hyacinths? Any chance I could get them to overwinter in a 3x5 foot black plastic horse trough in this unheated but sunny space? I did keep them all last year, and they did fine, but the GH didn't get below freezing...

Best rule for a cold greenhouse is to keep anything that is just not quite hardy enough to survive the worst of the weather in there. We keep all sorts of things in ours over the winter (especially those which don't like winter wet which is the main killer here). So the Agapanthus and rain lilies should do well in there over winter.

As you know the last 4 months of the year is the preferred time for sowing seeds in Europe, but perennials can easily be sown almost year round (hot and cold weather exceptions stand). Why don't more people sow direct in Autumn (hardy plants) when the soil is warm? Or even sow now 'til November in trays so the seeds get several periods of warmth and cold to break down the seed coat? Saves on greenhouse space over winter *G*

Terry what I did with mine last year was I sowed all my seeds I ususally put out in the fall or winter. That way I didn't have to worry about keeping up with flats outside all winter and the dogs getting into them or them blowing away.I could also keep them marked better too and didn't have to worry about losing the markers. As for the bulbs I had my canna's and dahlia in there to dry out and somehow time got away from me and I didn't get them stored elsewhere and they all froze.I am curious to see what others say about the water lettuce and hyacinths I was figuring I would send them to warmer climate sure would be nice to keep some for next year.

you may want to use an aquarium heater to keep the water from freezing. Remember, it will only be a few degrees warmer in there unless you use a heater. Things should be safe unless the outside temp goes below 25*F.