The greenhouse-esque structure is great for plants like spinach, lettuce, beets, carrots and cilantro. Make sure to choose plants and vegetables that will grow fine without protection after about two months or so in the hoop structure, for best results, Growing for Market recommends.
1. Build the frame
After measuring and marking out the hoop house site, you’ll need to build your frame. Choose rot-resistant wood for the base. You’ll need four 2×6 boards on edge (if your hoop house is smaller than 14 feet, opt for 2x4s.) Screw the frame into place using corner joints and wood screws. You may want to put some stakes in the corner of the boxes to keep the entire thing in place while you work on the rest of the structure.
2. Set your base pipes
Your PVC pipe should range from 18-36 inches tall. Harder ground will require shorter pipes. Use a sledgehammer to pound a pipe at each corner and then every 3-feet down the sides. Make sure your pipes set closely to the inside edges of the frame. Pound the pipes down until they are equal to the top of the frame.
3. Hoop pipes
The size of hoop pipe (that creates the main structure for your covering) is determined by the size of arch you’ll need. For example, an 18-foot-wide hoop house requires 2 1o-foot long and one 20-foot long pipes for each hoop. When purchasing your pipe, ask for one pipe in each pair to have a flared end so that the pipes will connect.
To install the hoops, lay your pipes on the ground. Slip the end of one pipe into the base pipe, bend the pipes so the other end fits into the base on the other side and use a drill to bore through the pipes and ground frame (only one side for now), push the hoop all the way down and then add a carriage bolt into the holes.
Make your arch structure sturdy by adding horizontal pipes to link the hoop together. Most hoop houses require at least one purlin on the top, two more down the each side of the structure. Depending on your climate, you may need more to provide stability against strong winds and rain. Attach with carriage bolts.
To make your hoop house retractable (bottom up), attach 1×2 wooden hip boards about 3 feet from the ground. You’ll attach the main plastic pieces to these boards.
5. Attach the plastic
Choose a high-end greenhouse plastic. The material is sturdier and lasts longer than cheaper plastics you’ll find elsewhere, plus the greenhouse material offers better insulation for your plants.
When attaching your plastic, make sure to leave a foot or so of extra space along the edges and about 2 feet of extra plastic on the ends. Toss over your structure and tighten as needed. You can attach the plastic using wiggle wire and a track. Try using two layers of plastic for better insulation.
Your flooring should include enough space for you to walk in and out of without disturbing any plants you have lined inside. Use a lightweight material for walkways so the soil beneath is mostly undamaged (straw, sawdust and mulch work well).