The features of this particular greenhouse that sold me on it was the maximization of passive design. A reflector on the north wall focuses low angle winter sunlight on a +-7' diameter pond/pool inside the greenhouse. The pool is warmed in the daytime and cools, releasing the energy at night, pretty much preventing any freezing even here in central PA. A small pump and waterfall keep the water oxygenated (and the goldfish happy) and prevents temperature stratification. It also has small fans that circulate warmer daytime air through 4" tubes under the soil, keeping soil temperatures warmer. It has automatic temperature controlled vents and drip irrigation from Dripworks so it's self watering and self thermo regulating.
This allows growing of cool tolerant plants into and through winter (though growth slows a lot when solar energy is low). Also enables growing of things like tomatoes and peppers earlier (and peppers love the greenhouse). It also allows growing a few things that would not live in this zone, such as a bay leaf tree and some Jasmine.
It's also a peaceful and nice place to garden and work, even in winter.
The stem wall goes directly on packed gravel, no foundation needed.
The higher framework is built working off of scaffolding.
First piece of glazing is going up.
Shell almost complete!
The north wall reflective material is stapled into place.
Clay drilling the holes in the sheet metal that will be painted and bolted together to form the water tank/pond.
Together and lined!
I used landscaping blocks to build the walls of the beds inside the greenhouse.
The crew post build! Dad was super instrumental as always, Chelsea did an immense amount of the build work, Amanda and the Growing Spaces crew round out the major players!
Together! The pink insulation board was eventually buried, it's one more piece of protection against freezing.