DIY High Tunnel Hoop House Instructions

This is for a DIY hoop house / high tunnel build utilizing a pole bender with the top-rail and wood purchased locally.

We have 2 instructional videos, a quick start version, and a longer detailed version.
These instructions utilize a hoop bender to bend your own hoops.

Purchase top-rail at any big box hardware store.
Using a hoop bender videos

Keep scrolling for our simple guide, or

for printable & more detailed instructions:
Click here for printable PDF

Notes on spacing & sizes...

Our instructions assume ground posts and bows every 4 feet. We sink the ground posts 2 feet into the ground, allowing for higher tunnels and stronger frames.

20-24ft houses in high wind areas should consider deeper ground posts and/or running purlins on both sides of the ridge pole.

1. Set Location

Consider the suns path and if any objects will cause areas with shade during parts of the year.

2. Square your area

Mark each corner of your greenhouse area using a tape measure.

Then, measure diagonally, making sure the diagonal measurements are equal to each other.
Adjust corners until each length, width and diagonal measurements are equal.

3. Ground Cover

Lay down weed barrier & secure with staples.

4. Ground Posts

With the corners marked, lay out your ground posts, using twine & a line level as a guide for evenness at ground level & height.
Use the ground post driver to pound the post into the ground, leaving the bottom hole roughly 2" above the ground. Check for levelness as you go.

Making your own ground posts? Check out our more detailed instructional PDF, or watch the video at the top of the page.

5. Attach Baseboards

We use 1" x 8" x 8' white-wood ledger boards. Cut a foot off the first board so the ends don't meet at a post. Attach board ends with a scrap piece of wood.
Use a 1/4" drill bit and drill through the wood by going through the previously drilled hole in the ground post.

Insert a 4" x 1/4" tap bolt& tighten with a washer & nut on the outside

6. Bend Poles to Make Hoops

Check out our videos if you haven't bent hoops before.
Hoop Bender Videos
Lay out the poles with them all facing with the 'swagged' (male) end in the same direction. Mark each pole at 9" on both ends.

This mark will tell us where we insert the pole into the hoop bender and how far to insert our poles into the ground posts.
The number of 10 ft 1-3/8" top rail poles screwed together per hoop is determined by the high-tunnel width:
10-12 ft wide (2)
20 ft wide (3)
24 ft wide (4)
After bending the poles, join male and female ends and screw together with 3/4" self-tapping screws.

Be sure not to place the screws on the top of the hoop where it would rub against the plastic.

7. Install Hoops in Ground Posts

Use the line you previously marked at 9" to know how far to push your bows in.

After setting all of the hoops into place, you may have to adjust some of these in or out to make all of the hoops look even when viewing it from the ends.
Once satisfied use your 1/4" bit to drill through the hoops (at your pre-drilled hole) in the ground posts. Attach with a 2-1/4" hex bolt with washer and nut.

8. Install Ridge Pole

Once all hoops are secured in place, begin inserting your ridge pole into the cross connectors or spring slips. You will be using 1-3/8 cross connectors.
Place & center all your cross connectors in the middle of the hoop which should be the highest point.
Use 1-3/8" fence top rail poles also used for the hoops as ridge poles. Slide each pole through the cross connectors and connect each ridge pole together by inserting the male end into the female end and securing with a 1/4" screw (again from the side or bottom but not the top).

Stand back away from your greenhouse and adjust left or right until the whole connected ridge pole is straight.

Before tightening the screws on the cross connectors, ensure each bow is 4 ft from each other, then tighten or screw the cross-connectors.

Make sure the ends of the ridge pole is flush with the end of your greenhouse by cutting off the excess from one end with a hacksaw. Cover the end with duct tape.

9. Install Hip-board

If using roll up side walls, these are required. If not, we still recommend them for 20-24ft structures for extra stability.
Set hipboards as high as you want your roll up sides to go.
We typically place the bottom of the hip board about 36 inches from the top of the ground post.
Mark each hoop at your desired height
Line up your boards on the marks and use a clamp to hold in place. Drill a 1/4" hole through your board and then through the hoop. Place a zinc plated 1/4" x 4" carriage bolt through the wood and attaching with a washer and nut on the hoop end. **Note board will go on the inside if you don't plan on using roll up sides.

10. Install Lock Channel & Spring Wire

Install on the baseboards, hip-boards and around the end hoops.
It is helpful to pre-drill the holes before installing (at least 4 holes per 6.5′ piece). Be sure that the lock channel is installed straight from one piece to another to cover channel edges where plastic may snag.

Use a clamp to help you keep the channel in place while you bend it along the curve. Your lock channel should easily bend to the curvature of your hoops.

11. Build Endwalls/Door Frame

Install the baseboards running across the ends of the high tunnel. Connect to the end ground posts using a 4-x1/4" carriage bolt.

Installing the Door Frame

Take the width of the door you want to build and divide it by 2.
  1. Measure from the center of the hoop in a straight line and put a mark on each side on the hoop equal distant.
  2. Then place a 2" x 4" board from the ground up to the mark with the wide sides facing each other (skinny side facing outside). Trace the top and bottom of the curve from the hoop onto the 2" x 4" and then cut the top mark with a jig saw.
  3. For the bottom mark you will cut out a 1-3/8" deep notch. This is how you will anchor the stud to your hoop. You want the 2" x 4" to be just slightly shorter than the top of the hoop. Repeat on the other side of the door frame.
  4. To attach you will drill a 1/4" hole through the hoop and notched 2" x 4" and insert a 1/4" x 4" carriage bolt into the hoop and through the wood.
  5. Secure with a washer and nutagainst the wood. The bottom of the stud should be behind (toward the inside of the greenhouse) the baseboard. Then use a bubble level to level the stud and secure with 2.5" wood screws through the baseboard.

Door Header

Determine the height you want to make your door. Add an extra 7/8" to account for the reveal around the top (3/8") and bottom of the door (1/2"). Measure up from the baseboard along one of the inner door frame boards to that measurement and make a mark. Repeat for the opposite side as well.

Cut a 2" x 4" board to fit in-between with the bottom lined up with your marks. Make sure your header is level using a level and adjust as needed. Secure your header using 2.5" wood screws by screwing to your posts. Cut another 2" x 4" to fit directly above your header to form an L as a header. This should be flush with the outside of the lower header piece. Secure this piece with the 2.5" wood screws as well.

Now you want to install posts on the sides to form an L similar to how you did the header. These provide areas to secure your wiggle wire lock channel later on. The easiest way to measure these side posts is to place the bottom on the ground and just mark underneath the hoop and cut. Secure these additional side posts with the same 2.5" wood screws.

12. Build or Install Door

Pre-assembed screen doors work just fine. If you'd like to build a door, you can follow our instructions.
To build the door frame use two 1" x 4" boards to create a door frame. The width of your door should be 3/4" shorter than the opening and length 7/8" shorter. This allows for 3/8" of expansion on each side and top of your door when it gets wet. Allow for 1/2" expansion on the bottom of your door. To provide your door some support we sandwich plastic and chicken wire between the two 1" x 4" boards. You also want to add a 1" x 4" board in the middle of your door for stability, Install your door with some zinc plated hinges, making sure while installing to keep the spacing between the door and frame even.

12. Install Plastic Covering

From this point, make sure you can finish securing the plastic before you end for the day so it doesn't blow away on you.
Roll the plastic out and drape over the length of the greenhouse, equidistant from each end. Secure the plastic only on one end by installing the wiggle wire from the top of the arch to the hip board.

Once the plastic is secure on the first end arch, move to the opposite end and secure the greenhouse plastic in the arch the same way, pulling the plastic tight as you go.

Install the wiggle wire down to the hip board.

We will install the remainder of the wiggle wire after we complete the roll up sides.

13. Install Roll-up Sidewalls

Skip this step if not doing our ventilation with our hand crank.
Connect 3/4″ EMT conduit along the length of each side of the greenhouse, using 3/4" couplings to connect the pieces together.

Extend the EMT a foot past the edge of the greenhouse on both sides. If you are using our 3/4″ couplings, use self-taping screws to secure the poles together.
If you are using a standard EMT coupling make the screws as tight as you can to prevent slippage. Roll the ends of the plastic around the connected EMT until the greenhouse plastic is tight and the pole is flush with the bottom of the greenhouse.

Install snap clamps every 2 ft to ensure even ventilation. Put a screw through each snap clamp for permanent installation. After all the snap clamps are secure, the greenhouse plastic should be hanging down taught.

Secure greenhouse plastic with spring wire

This is the time to install the rest of the wiggle wire onto the hip boards. Work your way down from one end to the other. The plastic should already be somewhat taught from the weight of the EMT conduit.

Install hand crank for roll-up sidewalls

You can install the greenhouse ventilation gear crank now. The wiggle wire should be secure on the top ends and at the hip board all along the sides first. The EMT on the roll up sides should be extending a foot past the greenhouse on each end.

Take a scrap piece of 1" EMT, about 3-4 ft, and hammered that into the ground near the edge of the 3/4" EMT conduit. Then put a 6 ft piece of EMT conduit about 2 ft down into this pipe and put in 2 screws at ground level to secure it.