Planning a High Tunnel

Like the high tensile fence planning post, this is what my notes look like in CherryTree, the notekeeping program I use. CherryTree is free and works on windows, mac and linux. Unlike the fence, the high tunnel might end up being different than planned. For starters, it's going in sort of a tight spot for rolling it and there's still a few stumps there that would be hard to deal with for a movable tunnel. I'll start out stationary and maybe make it movable at a later date. Time and wind got the best of a neighbor's quonset hay shed and I got some of the curved steel pipe sections thinking of a high tunnel. I've pretty much got the design figured out. Need to yank or dig or burn out stumps, then do leveling and dig down around sides for drainage. (and build the high tunnel)

1) Make it movable


$11.56 - Pressed Steel - Galvanized For 1 5/8" O.D. Pipe Track. Bolts Included. 5" wheelD

Decided against moveable for now.

2) Common Sizes

Farmtek economy model 20', 26' & 30' wide x 24', 36', 48', 72', 96' long Farmtek premium model 14', 20', 26', 30' wide x24', 36', 48', 60', 72', 84', 96' long Most of the above are 12' tall - premium also comes 10' 6" tall for their 14' wide model (from What are the typical dimensions of a high tunnel? High tunnel dimensions range from 10-30’ width x 9-12’ height x up to 96’ length

3) 24 pipes/sections

I have 24 sections of pipe that are 10 foot long. 5 or 6 foot truss spacing ( farmtek is 4 foot for premium - 6 foot for economy

4) Three pipes

That gives me 8 trusses with a 26' width(unless I do a slight peak in the arch) 5' truss spacing, will make it 35' long 24' x 35' works. 3 pipes is 75" tall(deflection), plus 5 foot sides would make it 11' - 3" tall 6 foot sides would make it 12' - 3" tall 5' sides gives 6' headroom at 1' in from sides Smallwood Fence & Pipe near me sells 6' fence posts Maybe 5 foot sides with slight peak in truss as below - will decrease width slightly but 20'-24' width works too Higher peak would help with overheating *Note; As per a revision below, due to film size, I'll be going with a 32' long tunnel and with my 8 trusses, that comes out to 4.57' truss spacing or approx 4'-6 7/8"

5) Truss Style

There's two common truss styles, quonset or gothic(which is really a gable with a curved peak & two flat roof pitches) but I ran across a custom greenhouse builder who actually does some that are more like a true gothic with a peak and rounded roof pitches so that's what I'll be going with. Might help with snow load which quonsets aren't good for. I'm using three 10' sections of curved pipe so I'll have to notch, bend and weld the center section to form the slight peak. I may even fabricate something to act as a ridge board to give it even more strength and to keep the truss peaks all in a nice straight line. The shape will be something like below

6) Here we go

- 3 pipe sections with middle one notched, bent and welded to form a slight peak 24' x 33' = 768 sq ft (840 x 2 = 1680 sq ft since it's movable) Sides are 4' - 6" (that truss might no be built just like that. It was something I did quick. Will have to think on it) Rough Draft

Note to self. Measure how tall you are sitting on the tractor and insert crude likeness into the above drawing.

8) Film

(less than 50 foot length incurs small panel charge) Sun Master® Pull and Cut Clear Greenhouse Film 6', 10', 20', 28', 36', 40', 48', 56', 64' wide & cut to length Example price - 36' wide is $5.35/ft x 50' long = $267.50 Will have to figure out ends plus top and sides to see what would be best size to order

9) Film Needs

I've been eyeballing this plastic size but have been doing so since the tunnel was a totally different size. However, I like the price and I figured out how to use it. I'll have to cheat on the ends at the corners. It will be several inches shy on the width, as seen in the image above(light blue = film pc), but the corners are already shadowed by a pipe and plastic attachment components. 42x60= $329.00 ($499.00 as of 9/17/19) Here's how the pieces fit on the 42x60. One side will have to be done in two  pieces and maybe I'll just do them both that way. That would give more options for cross flow venting. Updated at bottom of post


It says 32x60 just above but that's a typo, it's actually 42x60. So far I'm at $500 between the plastic film. I'll still need pipe for the wheels to roll on, pipe for legs and misc steel for attaching the wheel track pipes to something. What? I don't know yet. Something cheap and non-toxic. Wiggle Wire + Channel = over $200.00 (actually, almost $700 to use it on every edge of every piece of film - yowza)

10) Soil

Solarize the soil during July/August for the first year, maybe more, to get control of weeds. Run chickens through it first if we have them. They'll till it and kill the grass/weeds. We'll also have kunekune and goats but I don't know which will happen first. I do know the fence is getting done first so we can get these big barking white dogs away from the house. They're keeping us up at night. One's a Great Pyrenees and the other looks to be an Old English Sheepdog mix. We'll see how long his fur gets. If after the fence, we get pigs and goats, I could run the goats through the tunnel spot, then the pigs, then chickens, along with as much compost, garbage and other organic material as I can get a hold of. The goats can eat it down to 4-5" and then the pigs would eat most all the rest of the vegetation and then the chickens can clean up all the crumbs in tiny bugs. All of them will be fertilizing it at the same time. If I can get a hold of restaurant/grocery scraps, I could feed them Karl Hammer style. One nice thing about getting animals is the manure. As it stands, I have all the leaves I could ever want and a little kitchen waste but not enough to maintain a pile. I can also get all the sawdust I want.

11) Bed Layout

I have no idea. I do have a small tractor but it's got 24" of clearance between the tires and it's not an ag tractor; more like landscaping/turf so it doesn't have much ground/crop clearance. I could use it to shape 24" wide beds, lay plastic mulch and run drip tube all in one shot. I've thought about making some 2" wheel spacers for the tractor which would give me 28" beds. Those long straight beds are more efficient to put row covers on too.

Great for growing all the same crop But this is to feed us, not to become market gardeners, although both would be nice. Beds going the other way are interesting but would be more manual labor and harder to design and install a drip system into.



Looks like they may be using a hose for something and I guess those are boards for walking paths? Here's Eliot Coleman style. Probably a bit much to start with. Pretty intensive and we'd probably get overwhelmed and exasperated. Now that's a water hose.(this is Elliot Coleman's)

This one's not bad. I could do without the green grid to trip on and the commercial mulch. Not sure about the lateral walkways. Now that's where a short board or something would come in handy. Good variety and still in long rows basically so some things can be done by machine. Hey look, another water hose. Everything I've read says one benefit of a high tunnel is that by using drip irrigation, there's no more wet foliage which reduces foliar diseases. This begs the question, Why does everyone have a water hose? Spot watering?


The more I've thought about it, I think something like above would work good. I can still use the tractor for bed shaping, laying drip tape and plastic mulch all in one shot and just not plant full length. Break it up with a few cross walks or just transition from one crop to another without a gap. I think one gap half way down the length might be handy though.

12) Irrigation

One thing that bothers me about plastic mulch and drip tape is that they're both too fragile to be reused. That means throwing it away and buying new every year. Might as well shop for shoes at WM and buy tools from HF while I'm at it. I've read everything about high tunnels I could get my hands on but haven't seen irrigation for movable tunnels addressed. Something else to ponder. We don't have a well yet so I go down the hill to a spring fed creek and fill a small tank that I tow behind the little tractor. Definitely going to have to harvest rainwater off of the tunnel. That would have to be run through a sand filter to use it for drip irrigation. Soaker hoses? PVC with tiny holes drilled in it and cover the PVC with mulch asap so the UV rays don't disintegrate it? Whatever I use, it will be running off an RV water pump at 3gpm and 45psi or by gravity and a tiny amount of head pressure. Just did some quick window shopping and it comes to $221.00 for a small drip system with programmable timer. That's using the drip tape that's hard to reuse. A 1000' roll has to be purchased and I figure 9 rows 32' long x 2 for the tunnel being movable and that comes to 576'. (=288') I'll have to see if I can whittle that down to an even 250' or 1/4 a roll. 8 rows @ 31' works out to 496'. At $60/roll, that would be $15/yr which isn't too bad. The rest of the components are more permanent although some of it is white PVC which will need to be kept shaded since it has no UV protection. Then in Spring and Fall, there's always the occasional 22 degree night to worry about. That means a tank heater, the main supply line buried and all other components being inside the tunnel with some of it wrapped with pipe insulation(there's my pvc shade) and the rest under floating row covers. Speaking of which.

13) Row Covers

The covering comes in three weights, light, medium and heavy with no thorough explanation as to what the different weights are for. Heavy comes in 500' rolls, light in 50, 500, 1000' and medium in 250' or 500'. Need to keep in mind my 8 rows at 31' mentioned above to utilize 250' of drip tube. 8 rows x 31' = 248'. That makes the 250' roll of medium weight the best choice. Even that is $120.00 so I better be gentle with it and make it last for years and years. I'm starting to understand why most growers say they don't increase profits with a tunnel, even though tunnels give nearly double the production of the same area of open field growing.

14) Total Cost

Well I'm at $500 for the tunnel film. I think I'll pass on the $200 wiggle wire and track this time around and figure out a different way to attach it. Here's the drip irrigation components and row cover material.

$500+$341=might as well call it $900 and I still need pipe for legs and something for the legs to attach to and for the tunnel to roll on so we can call it $1000.00 if not a bit more. Not something I'm ready to do this Spring. I'd rather have the perimeter fence first and that's going to cost around $1500.00, plus I can easily spend a year getting a place prepped for the high tunnel. A little earthwork to do, stumps to deal with, trees to cut down for more morning sunlight, soil testing and amendment and some sort of base or foundation for the tunnel to roll on and as a weed and vole block. When/if I run some animals over it, I'll make it a stale bed for a while to get rid of more weeds before the tunnel goes over it. Update; 8/28/2019 I just copied and pasted this from another CMS I was trying out. Unfortunately there's lack of themes for the other one. Bootstrap is it and there were also a couple of bugs due to it being one developer only. I'm back to WordPress. (and for now, with a boostrap looking theme LOL)

After looking at the garden area all year, I'm definitely going with a stationary tunnel to start. It's just too tight of s spot right now. This fall, I'm going to dig up the grass that has been growing like mad this year, flip it and let it sit like that. I'll also cover it up with a think layer of straw for winter and prep drainage around it. That way it will be ready for a tunnel next year.

I won't be doing the drip system for the first year, nor will I be be growing under plastic. I can get straw in round bales for $20-30.00 to keep the weeds down Update; 9/17/2019 Sitting here drinking my coffee, having just put a couple of books about high tunnel growing in my amazon wish list, reading over this post and just noticed that I don't address the cost of plastic mulch.

Also noticed where I had planned to get tunnel cover poly, has gone from $329 to $499 - The downside of planning too far ahead and/or taking too long to get things done. Prices just keep going up. Looks like close to $100 for a 3x2000 ft roll of plastic mulch as of now. Much to my surprise, the items in my farmtek cart above have only gone up by $10.00 which is due to the drip tape being a different brand and a penny more per foot for 1000 feet. I'll have to re-shop for cover film as $329 to $499 is quite a jump but IIRC, the $500 was what everyone else wanted so I guess bootstrapfarmer was an anomaly at the time.

$500 Film
$200 wiggle wire & track
$350 drip components
$100 plastic mulch

$1150 total

Or $500 for the film and approx $300 for misc steel, parts and pieces to make doors, attach film etc. and $150 for 4 yards of compost to get us started.  Once the chickens are full grown and we get some goats, we'll be able to make our own compost but this soil needs some initial help and St Louis Compost has certified compost for $32/yard. Four yards will give me 2 inches worth of coverage, plus fuel to go get it. This still puts us at right around $1000 for the first year. I may go ahead and get the plastic mulch and just lay it by hand or I might get some straw this Fall to cover the soil for winter and plant under it next Spring. Now I'm looking at farmtek film again


Sun Master® Infrared Anti-Condensate Thermal Greenhouse Film

Infrared retention and anti-condensate additives mean superior diffusion rates, heat retention and tensile strength. This premier 6 MIL thermal film offers huge savings on energy costs. Keep the heat and lose the drips! • Co-extruded copolymer resin tri-layer construction offers maximum physical properties for superior film life. • Infrared (IR) additives provide excellent diffusion and absorb and re-radiate infrared heat back down to the crop during the evening hours, saving as much as 30% on heating costs. • Drip control additive is incorporated throughout the film and provides superior condensation control. • 88% light transmission. • 52% diffused light transmission means improved, more uniform plant growth. • UV stabilized for up to four years of film life. • Writing (this side to the soil) should be facing the inside of the greenhouse so you can read from inside the greenhouse. • Available in full rolls only. • Exclusive 4 year warranty.


This is the good stuff but it comes in two sizes, 24x100 and 32x100 and 24 foot won't do anything for me. I'm putting three 10 foot arched sections of pipe together and will likely mount them on 3-4 foot long legs. So the 32 foot would do the arch, then I need sides and ends. If my tunnel is to be 35 foot long, that will take at least 36 foot off of the roll for the main cover, leaving 64 foot for ends and sides but the North end doesn't necessarily need to be film. I'll have to draw things out but it would be nice to cover the entire tunnel, plus, have enough left over for a second top/main cover. That might require me to shorten the tunnel from 35 feet to 32 feet as 100' divide 3 = 33'-4" which gives me two top covers and an extra piece 32'x33'-4" for side and one end. Two 4 foot sides would take 8 foot off of the 32' leaving 24'x33'-4" which would do my one end. I imagine the West facing side panel would not last long either though.

Let's see if the sq ft of material is even there. Starting with my leftover 32'x33'-4" = 1066 sq ft End Cover 24x14 = 336 sq ft Side Cover 4x33'-4" = 133 sq ft  - need two plus one replacement for the West side 3x133 = 399 sq ft (call it 400) So 400+336= 736 which is well under the 1066 sq ft and in fact, would almost give me my other end. Comes out 6 sq ft shy of doing so but I haven't figured for a bottom board on the sides and the top few feet of the North end could be something else like metal or wood over the door(s). That should work. If my sides are in two pieces, half length of the tunnel, that's fine and the end would get some sort of door which will allow breaking that film up into a few pieces. It's four year film so for $500, I can keep it covered for 8 years. ($62.50 per year) I'll have 250 foot or row length so the 2000' roll of plastic mulch for $100 will also last 8 years. ($12.50 per year) and drip tape is $0.07/ft or call it 10 cents a foot after shipping or $25.00 per year for 250 foot. $62.50 $12.50 $25.00 $100 per year to keep in film, drip tape and mulch. We spend more than that in tomato based sauces, Ketchup, BBQ Sauce, Pasta/Pizza Sauce. I'm thinking half the tunnel could be in paste tomatoes.

One of the books I just put on my wish list is by Andrew Mefferd and he lists tomatoes, eggplant, cucumbers, peppers, leafy greens, lettuce, herbs, and microgreens as being the most profitable to grow in a high tunnel. We don't do egg plant and the only thing we might use cucumbers for is pickles(hamburger dill slices) though I will eat them on a salad(cuces not pickles). I'm the only one though so I guess I could grow a few dual purpose types. With trellising, they would take up little space and something low could be grown around them. (Looks like lettuce and carrots make good companions.) I'm lucky enough to have kids that like greens, Collard, Spinach etc. We all eat plenty of potatoes but I don't know if it's worth taking up tunnel space for. Maybe for a late crop or maybe even an early and a late crop of new potatoes with the main crop grown outdoors.

That's where the movable tunnel would come in handy. 2/3 of it in potatoes and the rest in greens/lettuce or anything I want an early start on. It could almost be moved 1/3 it's length on one month intervals, one direction in Spring and the other direction in Fall and plant something every month for a total of 9 months. That would pretty much fill up the year while having it sit in one spot for three months for the warm weather crops like tomatoes, peppers, green beans etc.

Wow, a lot of planning to do yet. I'll have to figure out what we want to grow and how much and then put them on a timeline. Just looked at wiggle wire and track again. IF I used it on every edge of every piece of film, it would be almost $700.00 Wiggle wire + track = $1.70/ft 6x32 = 192 (long edge of top pc plus top and bottom of sides) 8x4 = 32 (sides will be done in two sections each side so I need 4 ends) 2x30 = 60 (arches on top pc) 38+24x2 = 124 (arch plus side height plus bottom width x 2 for 2 ends) 408 feet total(for using it on all sides of all film pieces) 51 channels @ $9.82/ea = $500.82 63 wires @ $2.95/ea = $185.85 $686.67 but I probably don't need it on all edges of all pieces. I was just curious. The alternative is wrapping it around a smooth corner and then screwing something in place to hold it there.

I'm wanting to either do roll down sides or bi-fold side that hinge on the bottom and retract down from the top. In both cases, my goal is to cut down on the number of crawling bugs getting it and also to protect tiny plants from wind gusts while allowing plenty of cross ventilation. For roll down sides, the top egde would be attached to PVC pipe so I won't need any wiggle wire track there. Probably just tape it to the PVC and be sure the film wraps around twice even when rolled up because wrapping over itself will help hold it in place.(have to add a few inches to the height of that pc of film) There's some silver foil duct tape I've used that holds up really well outdoors. It's made for duct board or flex duct and is thin like box/packaging tape and is not the easy to tear aluminum stuff but looks like chrome to match the duct board.

<< Go back to the previous page