I am adding a greenhouse to my yard. The open garden area is is 6 1/2 feet wide by 44 feet long with the long direction stretching directly from E to W. At one end is a 8' long by 6' wide garden shed, and I plan to attach a hoop greenhouse to that shed. The greenhouse would be the same width as the shed. My chosen greenhouse floorplan is 6'X16'.

Originally, I simply wanted to add a month or two to my growing season and planned to use a 1 3/8" fence toprail frame, with 4" CDX ply perloins, and a high grade plastic film skin. Nothing fancy - I built my own radius bender to create the 70" diameter half-circle, on top of the 4'6 straight wall sections, stick the ends in the ground, and attach the purloins and sheeting. Then I was going to remove the sheeting for the spring and summer.

After a couple of weeks of research it ain't so simple no more. I have decided to reengineer my design to extend its usefulness and durability by using a Solexx 5mm skin, a water filled heat mass (probably 20 five-gallon square storage containers for 100 gals total), an r-24 foam insulated north wall, perimeter foam insulation 18" below grade, cinder block footings, and r-24 east wall with door. I hope this will allow growing 10 months/yr and will eliminate having to change the agri-plastic film cover every few years.

I am considering switching to a solar design (Quonset with a steep pitch north face), however, I am also thinking that the hoop design with the entire south half skinned in Solexx, and the entire north half well insulated would also perform well, and be much easier and cheaper for me to build. I would use a raised bed along the entire south wall, and add the water mass between the raised bed and Solexx skin.

Questions:

1 - Am I wrong that the upside-down U-shape will be OK?

OR Does the flat area of the glazed surface "need" to be more perpendicular to the suns rays to be effective (as in the solar design).

2 - Will the Solexx provide the necessary transmission to allow the water mass to accumulate the heat (it would be at ground level with a 1.5" air gap between the Solexx skin and the plastic jugs)?

3 - Still debating how to ventilate for Salt Lake City's 95deg summers, but time is running short. If I am going to have any chance to use it this season, I need to get it roughed in soon. I could use it for the tomatoes and peppers early, and then finish the project as the season goes on.

Thanks... Don

WooHoo!! spring is finally here... almost. Gardens, off-roading, the birds and the bees, and a bit of warm camping - life is good.

p.s... I had a garden specific, 3-zone watering system installed with my lawn system. There are perimeter sprays and two independently timed drip lines with standard faucet valves already installed. The yard is landscaped and there is concrete work. Building a greenhose that is wider than 6' would be a crazy amount of work for a hobby greenhouse. I can make it longer, but not wider. Good news is its a lot of input for the narrow space - not a whole lot of shadowing going on here.