I built the classic Elliot Coleman hoop house; 20' rebar/ PVC rods buried in the ground, greenhouse plastic over that buried in the ground, total length of 12'. 2 Vents and a door in one end.
This shape is a cheap and efficient use of materials. My older greenhouse has survived the harsh UV, hail, high winds, heavy snows, and generally wild climate of Colorado for almost 3 years with no significant damage.
However, it is an INEFFICIENT use of space. The roof is too low, and the sides curve down in such a way that it is hard to utilize the space. Persistent weeds grow out along the buried edge, and due to the buried plastic and the curve, they are hard to dig out.
Also, alas, Colorado is not Maine. In mid-February, we generally get a spell of warm sunny days (65+ F), followed by cool nights. Then during March it can dip down to 10 F or so. On warm, sunny days, the temperature soars, even with the vents and door open. Cool season plants are stressed, bolting or freezing out. Warm weather things can't be planted in there till the end of May ( the greenhouse will freeze if it hits 28F outside.) In the fall, the house stays hot and keeps cool weather things from being established. Without any thermal mass, the temperature was going up to 120F by mid May, while night time temperatures still dipped below 40F. Even with added Thermal Mass, (120 gallons of water) the temperatures ranged from 50-105, still too much of a range. As I add more thermal mass, I loose more and more growing space. Due to the curve, large barrels have to be placed far forward, increasing space loss.
How can I retrofit this hoop house to make it more efficient, space wise and temperature wise?
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