Thanks for the insight. Did some research into Walipini's , essentially a pit greenhouse. I really like the rocket stove heater, that, and a north wall lined with black drums could all together help keep the greenhouse at a good temperature. I dont know anything about growing in winter since this will be my first time living in such conditions, but I still wonder if a pit greenhouse could maintain the necessary temperature during below freezing days, the Walipini was designed for the southern hemisphere...hmmm?
Also, if anyone knows of ways to build thermal mass/cob without much clay, this would certainly be a help. I'm still brainstorming on where to place the thermal mass part of the rocket stove heater, either around the greenhouse interior perimeter or running across the middle of the greenhouse partially or fully subterranean. Seeing as I don't know the clay composition of the soil (or how to extract clay from soil just yet), I would like to have some clay-less cob alternatives available should this be an issue.
Thanks for the ideas so far!
Christa