Post your Geraniums in containers
I over winter my geraniums in the basement.
Right by a window like yours are. I give them very little water.
Do you repot in the spring?
Yes, the frame is for a bit of support, to keep the branches from getting too "open."
I keep my geraniums under lights during winter and they flower all the time. I also like making cuttings anytime I see a possibility.
They just keep on flowering during winter so I feed them a bit. I don't like to keep them in the dark during winter or dig them up and hand them like lots of folks do.
If you keep them in a bright light, they will behave like it is summer all the time!