This week we moved our hoop house from the St Louis Ave garden and rebuilt on our Chicago Ave garden. The house is 33′ long, 22′ wide and about 7′ high in the middle. We are using this hoop house to start all of our hot weather crops (i.e. peppers, tomatoes, eggplants, okra, tomatillos, husk cherries). We also used it to start our cabbages and brussels sprouts because we are going to plant them in the dirt that still needs to be moved over from the St Louis garden. On a normal year we would also be starting our Kale, Chard, lettuce, and a whole bunch else in the hoop house because it would be too snowy and cold to grow them outside; but since the weather has been so crazy warm this year we decided to try direct seeding them and covering each growing bed instead. It is so warm this year, that our volunteer tomatoes (tomatoes growing from the seeds left in the dirt from last year) are growing already!
Here’s how we built our hoop house:
Our hoop house is constructed out of 22, 10′ long, 1-1/4″ PVC Conduit pipes. We put two together and bent them into 11 arcs. Each pipe has one male and one female end, so 2 slide together easily to form a 20′ pipe. The arcs are secured to the ground using rebar and smaller diameter PVC conduit.
We began by finding a site that was big enough plus 4 feet on either side and 6′ on either end (72′ X 20′). Then we banged one 3′ long, 3/4″ nale into the ground leaving 8″ above ground where one of the corners of the hoop house was going to be. Then we used the principals of a 5-12-13 right triangle to make a right angle–one edge of which would be the front face of the hoop house, and the other would be a side. Then we banged 9, 2′ pieces of 1/2″ rebar into the ground, leaving 8″ above ground, every 3′ along the side line. At the end, we banged in another long nail. Then we used the same right triangle trick to string a line parallel from the side, 12′ away. We then banged nails in at the corners, and rebar in every 3′ along the line. When banging the rebar into the ground, we were careful to make them angle slightly in towards the center of the hoophouse–this will help us bend the arcs.
Then we slid 8″ long, 3/4″ PVC conduit sleeves over each nail and rebar (we actually slid these sleeves over while we were banging them into the ground so that we’d know when to stop). Next, we slid on 4″ or 6″ long, 1-1/4″ PVC conduit spacers over those sleeves. We alternated the spacers so that they would be 4″, 6″, 4″, etc. The 3/4″ sleeves help hold the arches in place. The 1-1/4″ sleeves are used as spacers to raise the whole house up a bit so that it is easier to move through. We used the longer spacers when the end of the arch was female, because 2″ of the spacer would slide into the end of the pipe. Since the spacers were alternating, so were the male and female ends.
After our rebar was banged into the ground, and the sleeves and spacers were slid over we slid the female of one 20′ pipe over the sleeve and over the 6″ spacer. Then we carefully bent the 20′ pipe into an arc and slid the male end over the sleeve and on top of the spacer on the opposite rebar.
After we had all 11 arcs put up, we strung a thick (1/2″ish) nylon rope along the spine of the arcs and zip tied them to the place where the two pipes connect in the middle. Each zip tie wraps around the male end and sits right up against the opening on the female end. This rope is used to help hold the arcs vertical to the ground. First we used a 2′ earth anchor (which is probably overkill) to connect one end of the rope to the ground. Then, I stood at the side of the hoop house and held the arc vertical while my friend Ian got on his tippy toes, poked the ziptie through the rope, and wrapped the zip tie around the pipe so that the pipe would stand vertical. While doing this we were careful to not pull tightly on the rope, because that would begin to slowly pull all of the arcs off of vertical. Once we had secured all of the arcs, we secured the other end of the rope to the ground using another earth anchor.
The next step was to pull the plastic over the arcs. We got lucky and had a windless day to do this. We pulled one side of the plastic over so that the it was centered over the hoops. We could tell where center was by the creases where the plastic was folded for shipping. There were many feet of extra plastic along each side of the hoop house, and a bunch extra on the ends as well Once it was over we quickly covered the 4 edges of the plastic with bricks to keep it from blowing away.
To hold the plastic down for good, we began by cutting one 10′ long 1″ PVC conduit pipe in half. Then we used each half, plus 3 more 10′ long pieces to make 2, 35′ pipes. We took the bricks of one side edge of the plastic and gorilla taped it to one of the pipes. The we rolled the plastic up with the pipe until the roll came taut against the plastic hoops of the house. Then, using fence hardware, we secured the pipe to a 2′ earth anchor that we screwed into the ground at both corners. Next we repeated this on the other edge. Then we dumped wheelbarrow loads of woodchips along the edge, one load per space between pipes, to make sure those pipes weren’t going anywhere. We also secured the pipes to earth anchors at two points along the middle of the run. We had our plastic blow off in a big storm last year, so we made sure that wouldn’t happen again!
For the faces, we cut the plastic along the face up the middle. Then we used gorilla tape to secure the plastic from ripping beyond where we wanted by taping the end of the cut on both the inside and outside. Then we wrapped the two flaps of plastic around 8′ pipes, and secured them to the ground at each end with earth anchors, fence hardware and carabiners. Just to be careful, we also lay bricks along the openings at night.
I’m pretty happy with how this design worked out. It was pretty cheap to build, it is sturdy, and it opens/closes easily. Here are some pictures. Some of them are from last year, and some are from this year. I kinda got tired of describing the process, so if you want more detailed information, let us know.