This past year has been frustrating one for projects on my property, mostly due to a new
job and young family taking up most of my time, but it's all good.
I did however deal with the frustrations of a crappy above ground greenhouse this spring, freezing, blowing away in the wind, getting too hot, etc.
I went cheap and it ruined the fun for me.
I am in the planning phase now for a sunken greenhouse similar to a walipini/
mike oehler type
underground greenhouse and will be buying Oehlers
books this christmas. So far I've got: Facing south, at an angle of latitude +23 degrees, with good polycarbonate glazing, and a passive
solar mass behind the north wall.
I might be fine with this not being a year round greenhouse and just being a growing season extender, but year round would be cool if I could utilize multiple tricks to keep the structure above freezing temps. I do believe I can have a pretty solid budget for this.
For now I am trying to get some
plans on paper and had a few questions for those in the know.
-The pit walls/foundation, I see
alot of cement blocks, I would prefer to avoid that due to cost and deficient skills in masonry. I'm not against it though, are there ok alternatives I could try. I currently have as much
wood on my property as I'd ever need, including straight white pines that need thinning, and red oaks that are dying. Neither of those woods are super rot resistant, but might work if I were to dig them in and cover them with a plastic moisture barrier right?
-Insulating, inside or outside the foundation wall? both?
Should I plan on insulating the earth mass behind the north wall or is that better to be non insulated?
-The actual growing beds, what height in the greenhouse should they be to maximize growth? I've seen alot of terraced looks, I just don't want to excavate deep and have my plants not get
enough sun.
-How effective is the cold sink pit? i assume this will be part of the
mike oehler book, but it seems like it could be alot more digging.
Thanks to anyone with some thoughts, I'll certainly be posting pictures once I start.