Winter in the GH & PT

I’m thinking about adding some power out in the largest greenhouse, I don’t want to heat it electrically but wouldn’t mind adding some additional lights in there. Maybe pop them on a timer to trick what’s in there to continue growing. I’ll have the means to cloche the beds to double insulate them, I could even add some manure as a natural heat source below them. I think it will all depend on getting the light right, and that’s new ground for me.