I'm sure the answer to this is somewhere on this site, but what type of timber did you use in the berm shed and green house? Is it alright to use pine, as long as thickness is compensated for(since it's a weaker wood), and the appropriate measures are taken to prevent rot?
I don't know if this is the best place for this note, which occurred to me when I read this thread.
There's a fairly recent book (~2010), _Self-Sufficiency for the 21st Century_, by Dick and James Strawbridge. Though it's a compendium of ideas on many homestead topics, I was particularly struck by "Making a Greenhouse Heat-Sink" (pp.118-9). This article's basic idea is to make a heat storage reservoir in the greenhouse floor, by digging a hole of about a cubic yard (meter), and filling it with fist-sized creek gravel. This type of heat reservoir has been used since the 1970's in active air-based solar heating systems.
The innovation here, it seems to me, is the simplicity of the air mover: it's just a small 12 or 110V fan that sucks heated air (in the daytime) from the greenhouse roof peak and circulates it thru the storage bin where it deposits its heat, exiting then back into the greenhouse. (This cools the greenhouse during the daytime, when it tends to overheat.) Then at night, the same fan moves _cold_ air from the greenhouse peak, again blowing it into the heat bin, where it displaces warm air already there, pushing the heat back out into the greenhouse. The simplicity is that the one fan just runs 100% of the time, pushing air always in the same direction.
I've not done any modeling of this idea, though it seems reasonable enough; putting some numbers in would show what size pit is needed for what size greenhouse. Building one (which I would like to do) would pin down how much mixing of the warm and cool air masses there would be, perhaps reducing system efficiency.
The article in the book contains a very nice graphic of the system (1 picture = 1000 words, etc.) I'd like to scan this in and append it to this note, but am not sure about copyright issues. Maybe other readers or staff could give input on this question.
Honest conversation is the most powerful of revolutionary actions.