DIY Low Tunnel Hoops

April 21, 2010

So I’ve been really into the idea of extending the gardening season as well as protecting my cabbages, Brussels sprouts and broccoli from the dreaded white butterfly.  I’ve been scouring the interwebs for a good project to take ideas from and ended up at Johnny’s Selected Seeds Quick Hoops Bender.  Cool tool, eh?  It’s also a cool $69 plus $32.45 for shipping.  At just over $100 US, I couldn’t justify buying it and shipping it to Canada to only make a few hoops.  I set myself to finding a do-it-yourself (DIY) solution.

When I first tackled this project I thought 3/4″ PVC pipe was the way to go.  I’ve worked with it before when building props for Halloween (my other hobby) and I was used to the fittings and cutting of pipe, etc.  After reading blogs and posts from different gardeners who’ve built their own low tunnel hoop houses, I realized that the PVC would be too fragile to overwinter in my cold climate.  If I was going to build something, why not build something that will last?

Enter  electrical metallic tubing (EMT), a.k.a. galvanized electrical conduit.  These metal pipes are used to run electrical wiring in houses.  All the sites I’ve read (US sites, I should add) mention how a 3/4″ – 10′ length of EMT only costs about $2.  Great, I thought, this will be a cheap experiment.  Checking my local hardware store, I found out the same pipe costs $8.48.  I looked online at Lowe’s USA and found their price was $3.27, a whopping 2.6 times cheaper than here in Canada (btw, 1/2″ pipe up here is $4.98 and $1.87 down there. Ugh.).  I decided the next trip across the border would have to include a stop to Lowes.

In the meantime, I needed to find a way to bend the EMT without the use of the Quick Hoops Bender or a pipe bender – a handy pipe-bending tool that I don’t have and don’t want to purchase.  The problem would be to create the arc that the 10′ pipe would need to have so that the ends of the pipe would have a 4′ distance.  Basically, I was trying to figure out how to recreate the pipe in this photo.

To start my experiment, I bought one 1/2″ EMT, one 3/4″ EMT and one 3/4″ PVC pipe, all in our high Canadian prices.

Reviewing the Quick Hoops Bender manual (PDF), revealed that each hoop was to be extended 16″ beyond the end of the bender, i.e., there would be 16″ of straight EMT on either ends of the pipe.  I pounded scrap rebar into the ground until it was at a height of 16 inches:

I pounded another piece of scrap rebar into the ground 4′ away:

I took my 3/4″ PVC bendy pipe and stuck the ends on the rebar:

Stepping back, I had a 10′ long and 4′ diameter arc!

It’s not as perfect-looking as the Johnny’s picture but I didn’t care.  I dragged out a large piece of scrap plywood and placed it behind the pipe:

I took a Sharpie and traced the inside of the arc onto the plywood:

My next step will be to drill screws at 18″ intervals along the line to create a jig around which to bend the pipe.  Having two different diameter pipe will help me figure out which one is more suitable for this experiment.  Once I’ve got a few hoops made, I can then put them in my garden and cover it with remay to protect all my brassicas.

Yay!

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17 Responses to “DIY Low Tunnel Hoops”

  1. yaquigrande Says:

    I like the simple nature of the jig but I wonder if the plywood will hold the screws while you’re bending the tubing. My pessimistic nature tells me that the screws will come loose, but experimentation beats pessimism every time!

    • Kathy Says:

      I’ve no idea and have been wondering the same thing. Another option is to pound rebar into the ground at the same intervals and bend it around that. I just really don’t want to buy any special tools.

  2. Eric Lilius Says:

    A friend of mine pounded stakes into the ground and used them as a jig for bending rebar for a 14′wide hoop house. It worked well for him.

  3. Sylvana Says:

    I am very curious to see how this works for you. I will be building a hoop house this fall and I was going to use PVC, but thought it would be better to use the galvanized pipe. If it makes you feel any better, when I went to price out the galv. pipe, it was $8+ here too. I think I might have been looking at the wrong kind of pipe if you were seeing it for $2 at Lowes.

  4. Paul Drowns Says:

    Your PVC jig will work but based on my own experience, I’d suggest screwing down the PVC tubing itself (@ 1″ intervals) and use that as a jig. Clamp the center point of the tubing to the center point of the jig. Two people, each bending from opposite ends, can form a hoop in less than a minute.
    I’ve successfully used this method on a barn floor and it works well.
    I am now playing with making a jig to mount on a wall to enable working upright.
    The problem with bending around screws or bolts alone is that they contact the galvanized EMT one at a time and tear the wood. Bending against a well secured arc of PVC distributes the pressure evenly.

    • Theodore Davey Says:

      Brilliant!! Best solution so far to avoiding cost of commercial benders (which, by the way you must buy one of for each diameter you wish to bend, plus they only come in two or three diameters, depending on which bender you select). My only fiddly proviso is that the EMT pipe center will not be the same as the PVC jig center. The EMT center will lie somewhat outside the PVC center, by an amount which will depend upon the diameters of the PVC you used for the jig and the diameter of the EMT you are bending. So if you need a really exact bend you might need to fiddle around with the PVC pattern. You could probably do this by holding a little piece of the EMT centered over the exact curve and then screwing in the PVC next to it to get the right spacing.

      Again, BRILLIANT!, and thank you.

  5. Ian L Says:

    You could always buy the hoop bender directly from the manufacturer!
    http://www.hoopbenders.net/3999rowcoverbender.html
    It’s a bit less expensive that way, $39.99 US with free shipping to the lower 48 US states.( Don’t know about Canada, would need to inquire. )

  6. spike Says:

    Hi.

    So how did it go? Trying to figure out if the electrical conduit is the way to go. Thinking of creating something like the gothic design hoop house with electrical conduit. Did you do any strength tests between the PVC and the conduit? Were you able to bend the conduit without a pipe bender? 1/2″ or 3/4″ conduit? Damn I’ve got too many questions.

    Thanks!

  7. southernhues Says:

    I saw people make a jig with a plywood back and pieces of 2×4 mounted on it at the Growing Power garden in Chicago. I saw it in use too and it worked well

  8. Paul Says:

    EMT over PVC any day. The functional life of electrical metallic tubing is substantially longer than PVC, it’s much stronger, and difference in cost is negligible. I know of 2 hoop houses made of fence top-rail that are 9 years old and still going strong.
    1/2″ EMT for tunnel hoops are best.
    I planted 90′ of tunnels last year, suffered almost zero insect damage, and extended the season to boot.
    I also built a 10′ x 24′ x 8′ hoop house out of 1″ EMT, and subtracting the cost of a 10′ Lost Creek bender, spent around $350. !5 indeterminate non-hybrid tomato plants buried me in blossom set and fruit.
    In the process of drawing up a complete set of plans and a materials schedule…

    • spike Says:

      Hey all,

      Stumbled on this old post again and thought I’d comment and update.

      Decided I wanted to build a 10′ x 50′ high tunnel hoop house. Turns out the 1/2″ emt was too weak for the serious storms last year. Upgraded and built a second high tunnel hoop house with 1″ and 1.5″ emt conduit. Maybe I’ll post my experiences with pictures. The 1″ conduit is way stronger like Paul says.

      This spring we’ll be using the busted 1/2″ emt for small low tunnel hoops over the raised beds. Will let you know about how that goes. Would definitely like to compare notes with you Paul.


      • Yeah… 1/2 inch is for low tunnels only! 3/4 inch will work if you set hoops 3 feet on center but 1 inch is best.
        I’ve continued modifying design and am now using 1 inch EMT to make caterpillar houses with no framing on the ends. It makes the structure 3 season but they are easy to take down and set up. Here in Maine, I decided that there is little reason to keep a house up all year.
        Mulch, row cover directly on the crop, and then plastic over 1/2 inch low tunnels is enough to hold root crops in the ground over the winter (good idea to choose varieties that are well suited though)

      • Jeremy Says:

        Anyone in snow country used 1″ emt for a winter Hugh tunnel? Most of the plans for winter tunnels involve peaking the roof to make a gothic style tunnel. The 1″ is largest pipe that I’ve seen a regular bender (non-hydraulic) for putting the peak on. I have a 12×48 tunnel with top rail, but I’d really like to make something snow worthy and 14 feet wide for winter greens (I can get 4 beds instead of 3). Glad to see lots of other folks out there are experimenting with this stuff!

  9. Kathy Says:

    Spike, I didn’t get around to trying it with EMT. I decided to wimp out and did it with PVC pipe. I laid remay over it and held it down with extra pieces of rebar.

  10. Greg Says:

    How do you fasten the plastic on top of the piping? As in what holds the plastic down?

    • Kathy Says:

      I didn’t fasten it – I folded the sides and ends of the remay over t-bars on the ground so that the fabric was pulled taut over the entire structure.

  11. Lulu Says:

    I used 1/2″ pvc pipe.to bend hoops in a raised garden bed. I stuck one end into the ground and bent the hoop over to the other end and pushed it into the ground. I did it by hand. It is holding up very well. It was less than $2 per hoop at Home Depot and took 2 minutes. Try it.


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