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low tunnel

Posted by little_minnie 4 (My Page) on
Mon, Jan 14, 13 at 20:14

I have been working out the low tunnel ideas for spring. On the MN forum there is someone else trying for the same thing so we have been brainstorming.
http://forums.gardenweb.com/forums/load/mngard/msg1022193222011.html?28

The problems I have are 1. can't ask to put a big permanent high tunnel on the 1/2 acre I rent 2. want to extend the season and also extend greens into summer with shade fabric 3. My beds are about 3.5 feet wide and paths about 2.5 feet wide= 6 feet for both.

So all the low tunnel needs are set up for Eliot Coleman's sized beds- just over 2 feet. So the 6 foot wide tunnel benders and 10 foot wide coverings will cover 2 of his size beds. Damn it, mine are wider! It makes sense to have them wider to make the most of the space but the usual 6 foot wide tunnels would only cover 1 bed! What a waste. So Soilent and I have been talking about making our own tunnels the way we want them. That is fine for the frame but all the FRC, film and shade fabric don't come in the right sizes!
So perhaps I should just give in and get the bender and make one low tunnel for each bed I want to cover, starting with 2. I can use EMT or whatever you call it, and the appropriate easy to find coverings.
What do you think?
If I get a bender should I go with the 4 foot wide and high one or 6 foot wide, 3 feet high one. Should I redo all my beds again sometime?


Follow-Up Postings:

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RE: low tunnel

you could use pvc tubing and rebar.


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RE: low tunnel

This is an idea I got from MSU hoophouse website. These are not your typical shaped tunnels, more rectangular shape. I know this won't work for snow country (outside garden/over wintering), but in a HH it will work just fine for me. I plan on using this type of low/high tunnels in my NRCS HH and in my garden when not being used in the HH. Use 1/2"x10' conduit bent to a 90 degree on each end. Cut a piece of conduit or pvc the height you want your low/high tunnel to be, slip your cut piece over 12"rebar (hammmer into ground half way), then slip the 90 degree end on (over/in) your cut piece. I didn't figure out what size fabric I would need bc this will vary in size for me (height of crop under). I will sew the fabric together if I have to. I hope you can understand what I'm trying to say here.
Deb


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RE: low tunnel

What's the rationale that makes a low tunnel ok, but a high tunnel not ok? Both are temporary structures that are exempt from property taxes. If it's the work of taking it apart when you're done, both structures have to be anchored to the ground, which typically involves stakes or earth augers, and those are the big pain to remove. Everything else bolts together and can be rapidly disassembled.


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RE: low tunnel

The difference in rationale MIGHT be the size difference, or just plain STUPIDITY on the rules part.


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RE: low tunnel

For years, I used 1" plastic water pipe that I fit inside 1 1/2" pvc pipe pounded in the ground. No bending needed, and they will conform to any width you make them. The plastic formed a natural arc and kept its shape. The down side is they're not fireproof!!


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RE: low tunnel

Brook, not much is. Look at your fire as a chance to start over.


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RE: low tunnel

Ack.
So are you saying it is better to go with homemade version rather than buy tunnel bender so I can make them the size I want? Remember it gets really hard to find FRC, film and shade fabric in the right width.


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RE: low tunnel

Check out "Environmental Green Products". They are a long way from home for me, but shipping was cheaper. Anyone know of somewhere cheaper?
Deb


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RE: low tunnel

Minnie, I would buy locally, you can get a bender at Lowes or most any lumber/hardware store where the contractors buy. They will have many sizes. As far as the shade cloth, mine are stitched together with a flat seam (like jeans), you can also order many sizes from several greenhouse supply stores and they will stitch them together.

I'm going to stitch the Agrifab together, just tacking actually, so that I can have the right size. I'm also adding hoops into the agrifab for the hoops. Also a string, to be able to pull the fabric over the hoops when needed.


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RE: low tunnel

You can buy benders locally?


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RE: low tunnel

Around here, yes. Do you have a Lowes? It will bend 90degree easily, anything else that's some work. It is a EMT bender.


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RE: low tunnel

I'm going to second (or third) the PVC idea. Its cheap, easy to set up and move, holds up to wind and though I don't really like the plastic factor, it lasts for a long time.
20' lengths with rebar in the ground can cover two 3 1/2' beds with a decent path between them. You could also widen it to cover more narrow beds. The 20' wide plastic film you would need is a common width.

I made one that was 100' long and used it for 10+ years taking it down every winter. After I bought my 30x96 hoophouse, the PVC has been sitting in storage. This year i'm going to put it back to use again as two 50' lengths.
-Mark


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RE: low tunnel

I don't want to deal with PVC as I don't have any clue how to work with and bend it and I have to do everything myself so no way. Rebar and tubing are what I mean to do. Dimensions are the problem.


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RE: low tunnel

Minnie, pvc will bend just by placing one end in the ground and stick the other end in another spot in the ground. Be sure that the measurement between spots are less than the length of the pvc. Pvc is the white/gray tubing that is in the hardware/plumbing section.

Go into your local lumberyard and ask for it. You'll see that you can bend the piece easily. You don't need anything to work with it except if you are connecting 2 pieces together. It's really the easiest tubing to work with.


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RE: low tunnel

Yes I have decided to just make my own out of 3/4 inch tubing. I am going to have someone sew two 7 foot wide row covers together and I can order greenhuse film in 28 feet and cut into 2 14 foot pieces. I am not sure about shade fabric. I think I will get 6 or 10 foot shade fabric with grommets and have the sides open and ties to the grommets.


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RE: low tunnel

PVC has some issues but ease of use isn't one of them. You bend them into arches by hand as they are made of bendable material.


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RE: low tunnel

Conduit or PVC is the easies to work with and there is no bending. Cheapest also check out youtube for many ideas.


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RE: low tunnel

Wow rhashell, you waited 2 weeks to repeat what many other people have already said. Thank!


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RE: low tunnel

Still stubbornly refusing to think about PVC. That freaks me out to think about bending it; I saw a thing about how it kinks instead of bending smoothly. Mother Earth News has a little info on low tunnels this month but mostly just hoops which I already use (little wire hoops are not low tunnels).
I am not making a walk in structure; only something that will cover the toms and peps in spring/fall and the shaded greens in summer and then maybe some greens in winter. A few feet tall and wide enough to cover 2 beds. I can sit on my scoot for picking, or hands and knees.


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RE: low tunnel

I'm going to put up another little PVC hooplet, about 12x50 in a few weeks. I'll try to take some pictures to show the process. PVC does not kink at all. It bends into nice smooth hoops.


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RE: low tunnel

I had some early failures with my tunnel construction in that the tubing I bought was not firm enough, even with wire shoved inside it. So now I figured out how to bend EMT into an arc with my foot and put that inside the tubing, up to the rebar. This makes the 10 foot EMT and the rebar together the length of the tubing which is 12.5 feet. I did 6 tubes last night and have as much as 18 to go.


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RE: low tunnel

Congrats littleMinnie, I saw a bender in an auction Sunday and thought of you, but James said it was only a 1/2" bender and implied that it wouldn't work.

Are you going to bury some rebar or something and then slide the EMT on it? If so, we drilled some holes and put a heavy screw into the EMT. We screwed the screw into the EMT til it hit the rebar and tightened. This helped to hold the EMT against the wind trying to blow it away. Even low tunnels would have some wind resistance.

We got our greenhouse because the people thought they could just put the rebar in but not secure it. Good for us, and since they had insurance, they got a new greenhouse installed correctly.


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RE: low tunnel

Can you explain more about the screw connection?


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RE: low tunnel

I guess I was incorrect, hubby and son did it. they used a smaller metal tube (we actually was using top-rail for chain=link fence), pounded it into ground, cut off top that had been bent over (sawsall, I think), the slide the greenhouse tubing over the toprail, drilled a screw threw both pieces (self-tapping, I think). then we put band boards around the bottom, screwing them into the ribs also.
I would take a picture, but it's all covered with grass grown over the connections now.

If we need to remove it,, we would unscrew the screw, pull the outer pipe, then have to pull the small metal pipe. We did not concrete them in at least.

I had a previous one that had a special attachment that looked like a connection with a tightening screw built into it.


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RE: low tunnel

Wish we could delete double posts.

This post was edited by myfamilysfarm on Wed, Aug 7, 13 at 18:50


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RE: low tunnel

OK any ideas of how to make the 10 foot EMT conduit and a piece of rebar into a 12.5 foot long arc? The poly tubing to connect it all was a fail. There must be some way to connect 1/2 inch rebar and 1/2 inch conduit without the conduit covering the rebar to the ground so I can get the extra inches.
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RE: low tunnel

We have several of these low tunnels - the one in the picture I modified to use as a cold frame in the spring for plants. The only difference is the plywood floor. IIRC they are 4'x10' but I usually put them end to end and screw the bottom plates together.They work pretty well but are a little difficult to store (if you remove the gusset brace they stack). I use a concrete form stake to hold them down in the garden (one on each long side in the middle). I tried these without the gusset and brace but they did not stand well in the wind. Maybe a gusset would be helpful for you.

Tom

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RE: low tunnel

to keep the emt from sliding all the way to the ground you could make a sleeve out of emt or pvc the same diameter as the emt hoop to fit between the emt and the ground.


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RE: low tunnel

I did do both a single and a double 'gusset' originally and it caved in so I took it out. The problem is I want wider than most people do so the stuff I have read people doing is fine for a narrower situation.
My husband is visiting the garden tomorrow and I will see what ideas he has for a connection. Honestly he is only slightly better at this sort of thing than I, but has no interest so it evens it out LOL.


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RE: low tunnel

I don't get it. this post has been going on since January. A 10' length of white or gray pvc cost about $1.50 each locally. 16" piece of 3/8" rebar driven into the ground (2 for each arch) 10' length of pvc will make arch 5' wide by 3-4' high. too big trim ,the pvc to fit. cover with film grow!!!! I have used these for years. I can set up 5x 25' low tunnel in less than a half hour. quick, simple no equipment needed other than hammer and a measuring devise...


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RE: low tunnel

But I don't want a tunnel of that width. I want one to cover 2 beds with a path in the middle which is 9 feet wide and needs more than a 10 foot piece of anything to make the arc. It needs a good 12.5 feet long item to make that arc.


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RE: low tunnel

my 11' x 15' high tunnel 1" x 20' pvc that size will get you 7' height in the center. since you want it narrower, you could either get more height or trim off 20' pie to desired size. I would just cover each bed seperatly. with a low tunnel.


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