Real food? - Mini vent.

A rock wall would give you a lovely natural look too <3 I found something pretty interesting involving stone structures. http://www.monolithic.org/homes/fea...n-earth-sheltered-dome-and-a-work-in-progress
Its pretty cool!

That is pretty cool!

A rock wall will hold a lot of heat and release it slowly and evenly, that is one of the basic designs in a passive solar house. However, in order to work properly, it will need to be isolated from the outside, like a wall behind it with an air-gap or insulation between the two. Otherwise, the heat will go to the outside and not stay inside the greenhouse.

The beauty of an earthen home or greenhouse is the sheer volume of earth that would need to get cold before your living areas get cold.

A friend told me the magic number is 4 feet. A greenhouse that has the planting beds 4 feet below the surrounding ground surface will not freeze. I guess her uncle made a living growing herbs for essential oils year-round in northern Idaho in a greenhouse 4 feet deep. Don't know if it is true or not.