Jenn how much land do you have?
How close to woods, where bears, raccoons and other critters reside are you?
I am in Minn. and have gardens in areas that reach down to the -40 below but normally peak at the -20 below area, how cold is your area.
If it is truly a sub-zero, -20 often area, a year round green house would really have to be a sub-terrain item. I.e. the floor is at least five feet below surrounding terrain for it to work without heating bills extremely high.
Even in lower Minn. 100 miles south of me, sweet cherries are at best a crap-shoot with failure most common.
The only thing I grown that is not for this zone is Hybrid Tea roses and they involve a lot of work being prepared for winter.
At that any one up here who grows hybrid teas will lose some near every year.
I totally bury them now but that is a lot of work and getting new ones started still involves a lot of failure.
