Converting an existing shed into a Bioshelter?

I've got an old shed that was used as a granary.  It's unisnulated, about 30'x20' with wooden walls, has great sun exposure, has water and electricity, and is fairly close to the house.  Since we moved into our property 2 years ago, I've been eyeing it with the thought that it would make a great greenhouse.  We live in southern Minnesota with harsh winters.

I live in Minnesota and am wondering what materials would be best for the southern wall and south facing roof if we are to transition it to a greenhouse-type building.  How much insulation should we put on the north-facing walls?

Aaron Rushing wrote:I've got an old shed that was used as a granary.  It's unisnulated, about 30'x20' with wooden walls, has great sun exposure,

Now this is a project I could get interested in....... Have you checked the solar alignment? if not here's how: Finding solar south

Would you tell me which side faces south?  the 30' or the 20' side?

Which directions do your winter winds come from on most days?

The long side faces south.  Great alignment, which factored into my vision for its future.

Nice that the building was oriented that way..... is there any winter shadows on the south side wall or roof?

What direction do the majority of your winter winds come from?

Would you post pics of the floor, walls, and ceiling?