Making Green Houses

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sand_puppy's picture
sand_puppy
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Making Green Houses

Here is an awesome DIY hoop green house building tutorial.

How to Build A 300 Square Foot Windproof Hoop House For Under $500. from Natural Living Ideas.  (Thanks Time2Help who posted this on facebook.)

This is a 12' x 24' x 6'8" size.

A frame is made of pressure treated lumber.  (A center frame/brace is made to strengthen it against wind.)

Rebar is hammered into the ground just inside the edges of the frame and 20' long 3/4" PVC pipe is bent into a semicircle and put on the rebar anchor points.  This makes the hoops.

Plastic and shade cloth are applied.

 

I would love to see other's green house efforts and what designs and plans others are using.

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High Tunnel

We have 6! Love them and think everyone should have one.

Our first two were PVC and we had issues with the greenhouse film interacting and being degraded by the PVC. The first few times we skinned it was with painters film from the local big box. There is no ultra violet inhibitors in the stuff, it broke down within a couple of months. We skinned those first high tunnels three times in the first year. Greenhouse film and steel hoops will save you money in the long run.

You need a high tunnel! Google "johnny's high tunnel pdf" for a GREAT tutorial.

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Johnny's Seeds High Tunnel (Hoop Green House)

Johnny's Seeds has an instruction manual that Rob was just referring too.

http://www.johnnyseeds.com/assets/information/9018_quickhoops-high-tunne...

Lots of good pictures and instructions.

The frame is build with the ubiquitously available 1-3/8" bar commonly used along the top of chain-link fences

Johnny's Seeds sells a bending tool (a "bender") for the purpose of creating the large steel hoops.

 

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Thanks SP

I have a hard time posting links, don't know if it is me or my browser....

That is the one, great info there.

If you do go with pvc, be sure to prime and paint it. It won't last as long as steel and will not be as resistant to wind or snow, but it will work!

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Thanks guys

Sand_puppy and Robshelper, 

Thanks for finding and sharing those resources on tunnel construction. I currently don't have the space on my property to build a low tunnel but these resources will come in handy for when I do. Eliot Coleman has a pretty good video on how to build cheap tunnels that aren't frame in or anything https://youtu.be/ovR-OZlul3w?t=11m29s. I definitely like the Johnnyseeds tunnels better, but for putting one up in the fall and taking down in the spring, this Eliot Coleman one looks pretty easy but it would be nice to have a door on one end. 

 

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Feedlot panel skeletons

Earlier this year, I constructed a chicken tractor off of plans I got via the University of Kentucky Cooperative Extension that used two 50" x 16' feedlot panels for the arch skeleton. Basically it was just building a frame for the bottom, arching the feedlot panels so they would fit inside both sides of the frame, securing the panels, and framing out the back supports and front doorway. The most tedious part of it was attaching the poultry wire to the outside of the tractor.

It occurred to me that it would be incredibly easy to make a high tunnel with the same strategy -- just adding more feedlot panels end-to-end to achieve the length desired, and bracing the frame against outward pressure every 4' or so.

Here's a link to the UK chicken tractor plans for anyone looking to do something similar.

http://www2.ca.uky.edu/agcomm/pubs/ASC/ASC189/ASC189.pdf

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My strategy for high tunnel

For me, my plan for a high tunnel is 1/2" electrical conduit, embedded into 2x4s on the ends. place the plastic over the ec, and then snap pool noodles over the EC/plastic, and fasten with ties. this holds the plastic to the inside of the pool noodle. then wrap the plasic around the end of the 2x2, and loop it back. the pool noodle now holds the plastic to the outside of the curve, creating a double wall airspace. For extra insulation beyond that, fill with foam peanuts, straw, grass cuttings, or other loose, cheap insulation.

Roll the ends, fasten with zip ties. then screw or bolt the 2x2s together for a strong double-wall (and maybe insulated) high tunnel.

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Make Green Houses Tall Enough to Stand Up In

My big conclusion from building a 5' high squirrel defense cages over raised beds is that when I can't stand up fully inside the enclosure it becomes an ordeal to enter and work there. I quickly find other things to do and let the weeds grow.

Conclusion: A green house must be tall enough to stand up inside. Or possibly, like a low tunnel, small enough to reach from the outside when the plastic is rolled away.

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My greenhouse

Unfortunately, I still don't know how to upload pictures here; but you can see my idea of a greenhouse on my facebook site, now. If anyone wants to import the pictures, please be my guest: I give permission.

https://m.facebook.com/photo.php?fbid=10154141963478831&id=774078830&set...

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Okay! I figured it out!

Greenhouse picture
Here you can see the double wall.  The inner layer of plastic is held to the inside of slit pool noodles, which are themselves clamped around the 1/2" electrical conduit by zip ties.  Once the noodles are all locked in place, 2x2s have 5/8 holes drilled halfway in to recieve the electrical conduit; and set screws hold it together.  The plastic is allowed to overlap everything by 9".  It is then wrapped around the 2x2s, and the edges rolled, to make a double wall. 

There are 4 sections here: 2 half-high walls, and 2 5' roof arches.  Once the sections are complete, the 2x2s are scabbed together with short pieces of 2x4 and screws.  Finally, we built triangulation:  an A-shapped support in back, and a delta-shaped support in front, screwing the triangulation to the ends of the 2x2s.

We next drove EC into the ground as stakes, and screwed it to the frame to hold everything down during wind storms. 

What you see here is before the A shaped ends were installed.

If you're in an area that gets really cold, like Colorado, I'd suggest putting dry leaves between the plastic layers as additional insulation.  You can also do like I will, and either put an incandescent lamp inside, or put a warm air vaporizer in there.  The vaporizer seems to work really well, in my experience.

By the way... the pretty little shed in the background, we built out of junk 5' x 5' pallets.  That was a fun project too.  You can see the construction process for the shed over at my facebook site:

https://www.facebook.com/photo.php?fbid=10152500878963831&set=pcb.101525...

Doing that without a traditional motor vehicle was interesting.  One of the pictures shows an electric-assist bike, with detachable dolly, for bringing the siding home.  Fun, fun, fun. 

Really.

 

 

 

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The rest of my high tunnel


 

So here is the rest of our double-walled pool noodle greenhouse.  We have a velcro-flap door; the bottom edge of the door is rolled for weight. 

Just as an aside:  the path is made of beautiful waste marble and granite, that we get for free from a local granite-and-marble-sink cutting company,

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hoop houses and dreams of a greenhouse
 

Thank you all for the motivation for me to finish my hoop houses. I've been thinking about a greenhouse, but there are 2 problems. First, I have a Nazi neighbor who finds complaining about her neighbors to be a fulfilling Endeavour. I had a buddy help me put up this shed this summer, and about a week later I had a notice on my door that I was in violation of code due to a complaint. Turns out the 2 neighbors who touch my property line who also have sheds in their side yards haven't been complained about, but alas. I was threatened with a $50/day fine until it was torn down or "moved" to the rear yard. I guess the thought of stick building a structure on concrete piers is foreign to code compliance and they thought this was a delivered shed that could be "moved". Anyway. This side yard where my shed was is on the south side of the house, which would be ideal for a greenhouse, but I'm not sure my neighbor would agree. Second my rear yard doesn't get that much sun in the winter and the south side would be much better. 

Until I get my greenhouse figured out (maybe I'll put up a 7 foot fence to block the view of my greenhouse from the road, although code says my fence can only by 6 feet high.....), I built some cold frames. The one is on hinges and I really like this design, but I'm going to rearrange my garden bed area for next year as I feel I have too much space between my beds. At that time I'll build some 4" wide raised beds out of 2x10 and then put a cap on the sides with 2x4. I'll post a video below to the kind I'm talking about. Anyway, thanks for the motivation and sharing your thoughts. 

Here's the link to a video on how this guy built a greenhouse, but he also has some video of his keyhole bed that is built with 2x10 and capped with 2x4. 

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Your cold frames are actually better.

You know something, Lambertad?  Your cold frames are better for your scale operation that a high tunnel.  The actual design purpose of a high tunnel is so that you can drive a tractor underneath, and farm in the winter.  It's better for larger-scale operations.  In my case, I'm trying to train my son to be able to handle all kinds of larger-scale projects, so a high tunnel was more appropriate.

That said, the design of my high-tunnel is completely as a temporary structure, and guided by the principles of a temporary structure.  If anyone objects, the structure can come down, be rolled up, and put away like a tent in less than three hours.  Or we can move it to another piece of property in about 5 hours. 

But the laws regarding temporary structures are different than those regarding permanent structures.  A temporary structure where I live MUST come down after a couple months.  For high tunnels, that's ideal.

I'd say, much more important to thriving after peak prosperity, is for you to get along well with the Nazi neighbor.

I'd work on that, if I were you.

 

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double layer protection

I haven't read Eliot Coleman's four season harvest yet, but I recently purchased it from amazon. I believe he said that for every layer of covering you increase the growing zone by 1.5. I'm currently in 6a, so a greenhouse gets me to 7b, and a cold frame/hoop house inside a greenhouse gets me to 9a. That would be ideal for me, but may be a stretch to have a greenhouse on my property. 

One of the biggest reasons that I like doing projects and improving my property is to learn skills. The buddy I had help me build my shed was a framing carpenter years ago. He taught me a lot during my shed build and I have confidence I could now build a shed on my own, although it would take a lot more time to do it by myself. 

Likewise, one of the reasons I would like to build greenhouse is to increase food production but also to learn how to do it. If I can increase my growing zone successfully where I currently live, that means I can take that knowledge and do it elsewhere. In the spirit of learning, I plan to start growing rootstock and grafting fruit trees next spring. If I can learn how to do those 2 things, I may be able to sell fruit trees as a second source of income in the future, we'll see. 

I don't plan on living at my current location for much longer. My wife is wrapping up her grad school in the spring and I finish next fall. We plan to move more rurally and to an area that allows better preparation, more freedom, and to have more land. We're young and it makes sense to do such. The build codes here are asinine, I can't drill a well on my property, we're essentially living in a desert (Salt Lake City) with the population projected to double by 2030 (Mormons really know how to have kids), and it barely rains from June-Aug. 

Thanks for your input about the hoop houses, I agree that they may be better for my situation at the current time. Also, sorry for hijacking the thread for my rant, but a greenhouse/cold frame combination may be perfect for someone living in the NE or Midwest and should be considered.

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What I'd suggest...

... you can take those cold frames, and make them suitable for citrus even, by the following modifications:

(1) One way is to wrap them in bubble wrap.  I actually had a lemon that we took up to Pennsylvania climate (actual location, Harrisonburg VA at high altitude).  It was in a giant trash can, and my father wrapped it in bubble wrap, and added a light.  It is fine.  A variant on that is to buy two plastic shelves for $30 each, and put your plants between them.  Wrap them, and put a lamp or warm air vaporizor in there.  That worked okay for us.

(2) Likewise, you can put a warm air vaporizer in your cold frames, and turn them into warm frames.  You can get these cheap from the thrift store, I find.

(3) If you want to learn how to make a high tunnel the way we did it, you have to go to Lowes and buy 1/2" electrical conduit, and an electrical conduit bender.  Also pick up pool noodles during the summer months, at the dollar store.  (If you want to do lots of them, you can buy them direct, probably at 60-70 cents each. They're styrene foam.) 
Make your cold frame with a double-layer the way I made my high tunnel, and you'll have the method down.  It really is easy -- I had my son do it.

(4) Funny thing about those nazis... just as in schindler's list, you can't really expect it, but sometimes all of a sudden they turn invaluable and righteous, despite their own best efforts.  It's still good to be friends.  However, your shed was a real fire threat to the neighboring house.  If it burned, it could have ignited the roof of the other house, judging from the photos I saw.  The proper way to do that is to plan it out, talk it up, get agreement on what would be acceptable, and then go through all the city hoops to get it approved.  Then you don't have to tear down... and the neighbors, if they have sense, will guide you to something that doesn't threaten damage (block construction, or concrete construction.  I do prestressed, so I know it's possible.  In fact, I can do homebuilt prestressed too.)

Anyhow.... I LIKE your cold frames.  May I suggest a Jeavons book, "How to grow more vegetables..." at growbiointensive.org ?

 

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Lambertad: How to attach plastic to PVC Green House Frame

I really like the "cold frame" / "low tunnel" green house you built.

In our location, we need a frame that holds chicken wire (or netting) over a raised bed during the hot months to keep animals out, then holds plastic over the same bed during the fall to extend the growing season into the cold months.

I am not sure how to attach the plastic to the frame in a way that it can be opened up like you did in post #12 above.

What did you do?

Winter is coming.

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plastic to pvc

On the hoop house that I have in the picture I used these garden clips from Amazon for the size of PVC I have, in my case, 1/2 PVC. They also make them for 3/4 and 1 inch PVC pipe. You basically put the plastic over the frame and then use these clips to hold the plastic to the frame. They're not great for removing and replacing as they will eventually wear a hole in the plastic over time. But if you just clip it to the frame and leave it there and remove it in the spring and place them on in the fall, it's not too hard on the plastic. 

The frame that is tilted back I installed on hinges. The caution I would make with that is that my beds are spaced entirely too far, 3 feet to be exact, and that works out to a lot of wasted space. If they were more like 18" apart, I wouldn't be able to tilt the frame back like that without smashing the plants in the bed behind it. Just something to think about as I plan to build new beds in this area next year and space them 18" apart for more bed space. I will admit, I really do like the hoop houses on hinges as it's easier to ventilate than the other 3. I found a video recently of a 2 layer hoop house, but I can't seem to locate it again. In that design, which was build on hinges BTW, you could do a layer of chicken wire on the inside frame or outside frame and use the other layer for plastic sheeting. Or, you could use 2 layers of plastic in winter to increase by 3 zones instead of just 1.5. I'll try to find it again as I thought it was a really neat design that I wouldn't have thought of. 

Finally found it - 2 layer hoop house plans starts about a minute or so in. Hope this helps, if you still have questions I can post some close up pictures if I ever get home after clinic before it gets dark in the evenings, or else it will have to wait until Saturday. Best of luck Sand_Puppy. 

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Shed

I should be more clear on the shed. The neighbor who lives next to me in the white house was likely not the one who complained. I talked to that neighbor and she was excited to see the shed. It was an elderly neighbor down the street who I suspect complained. She is probably in her 80s if I had to guess. She constantly walks the neighborhood and stops in front of peoples houses and just gazes like she is in a trance. Even the code compliance officer who I discussed my options with told me that my neighbor "complains about everything" and that she "keeps me busy" meaning her, responding to complaints. I understand the need to get along with neighbors, as I share produce from my beds with 2 of my immediate neighbors who also share their plums and veggies with us.  I also understand that I don't want to live within the constraints set upon me by overly restrictive code and will chose our next piece of property with that in mind, likely in a more rural setting with more setback from any streets/neighbors. It's all a learning situation and had my neighbor not complained, maybe I wouldn't have thought about choosing our next property based on a bias toward avoiding overly restrictive code. Thanks for the input and thoughts on how to appease/work with neighbors, though. It's always helpful to hear other peoples point of view.

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Double layered low tunnel/cold frame

Very nice idea, Lambertad.  Here is the video again.

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Thanks for those screenshots

Thanks for making those screenshots Sand_Puppy. I think this is the design I'm going to try next winter for at least 2-3 of my beds. I'm interested in seeing the difference between a double layer design and single layer design for myself. 

Adam

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Sketchup for design

 

I'm not sure how computer savvy people on this thread are, but I was messing around with a program called Google Sketchup today designing some raised beds. I've used the program previously for designing different projects including some rather large ones. I think it's a good tool to make mock ups of your thoughts and you can measure angles, rotate the design, and just get feel for how your plans will look before you actually make them.  Unfortunately I can't share my files on here that I know of, but here is a screenshot of my garden layout for next spring on my 22'x10' plot that I have right now. There is a learning curve to the program, but there are some fantastic beginner videos that can be found here, but you can also find great how-to videos on using the program on Youtube. Lastly, it's a free program if you download the non-professional edition. 

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Bubble wrap and noodles

I learn a lot from hearing the reports and seeing the pictures of others' projects.

I especially thought the use of noodles as spacers around a PVC hoop was very cleaver.  A way to make it double layered.

Michael's suggestion of using bubble wrap over a cold frame sounds really clever.  (It would probably need to be over a cold frame that is inside a bigger hoop house so wind and rain doesn't tear at it.)

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amleonard poly remnant sale

Hey guys, 

Just wanted to share some resources I recently came across for building greenhouses. 

The first is amleonard.com and specifically their poly remnant sale. I guess they have left over poly from various orders and they list them on sale and you can buy them. They seem like pretty fantastic deals for what seems to be high quality poly. If, like me, you are making hoop houses and don't need huge pieces of poly, then this may be a way to get them cheaper than you would otherwise. For small greenhouses, it also seems like there are large enough pieces that would work. 

The second is this forum entry from Permies.com. They have an entire forum dedicated to building, and more specifically to building greenhouses. The forum that I linked to has a video from a guy who built a greenhouse from cattle panel that cost him $1/square foot. I think that's an outstanding deal. 200 bucks for a 200 square foot greenhouse would be amazing. He's got a video or 2 in that link as well. Not sure if anyone else has tried the cattle panel idea and can speak to how well they stand up. 

Good luck with the projects. We had our first snow last night and my hoop houses held up well and the cold hardy plants are still alive!

Adam

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double layer cold frame How-to

OneYardRevolution has put out a How-to video on how he made his double layer cold frame/hoop house. Thought you guys might find this interesting since he's harvesting greens and carrots for salads in Chicago in December with this method. 

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Eliot Coleman's Easy and Cheap Greenhouses (pyranablade)

Thank you so much pyranablade for finding this and posting a couple of months ago. (I just found it)  I am moving here to this thread to keep the recent Green House projects in a common location.

Elliot Coleman does an amazing job explaining how to make several different iterations of green houses using:

a.  20' rebar, covered in plastic pipe, bent into a hoop, and inserted into a pipe set 12" into the ground.

b.  10' rebar inside Electrical Conduit that gives a gothic arch in the hoop.  A rope can be used to stabilize the top.

c.  A green house built on wooden skids that can be slid over the top of raised beds in the late fall to keep them growing during the winter.

Start about 11:00 min.

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Raised Beds made of wire and wood chips

It is sunny here in Virginia despite the late December date, and I'm trying out some ideas in the garden. 

Making raised beds with wire fencing material ("cattle panels") lined with a finer wire, then filled with wood chips around the edges and compost/topsoil in the middle.  This looks much cheaper than made of wood.

The video

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Attaching film to a high tunnel

Great thread!

We have found that wiggle wire is our favorite way to attach poly film to a structure. It can be removed and replaced to adjust tension and is pretty cost effective. There are two parts to it, a channel and the stainless steel wire. The channel can be bent to follow the curve of a hoop and screwed in place.

It can be found at Johnny's, Greenhouse mega store, Farm Tec, Rimol or any greenhouse supply.

I love seeing pictures of everyone's low tunnels, we use a spun fabric on ours called agribon. They work nearly as well as the high tunnels until we get a wind event, they hold their own up till about 40mph.

Here is another neat video.

 

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Best polyethelene. Multi-layering. Poultry fence vs bubble wrap.
  1. My 2016.01 notes on the best polyethelene after buying several brands: GreenhouseMegastore.com. (Shipped as "International Greenhouse.") "US made" 6mil 4year polyethelene. The best! Much clearer than Warp Bro. Much clearer than SunSelector. Ignore "ice clear" light transmission claims. Obviously, the better you can see through it--the better the transmission. This includes possible benefits of frosted plastic. Multi-layering the clearest plastic = frosting. And is superior to any single-layer special-effect plastic. (Including fancy plastics sold by Greenhouse Megastore.) Whereas if you start with low-transmission plastic then you simply cannot do as many layers before blocking too much light. Claims 33% longer vs. China made. In-stock departs 1 day from IL. 22ft x 55 = $150 + $28ship. 22ft x 100 = $300 + $50ship. -10% in January 2016.
  2. You can add 50% to the lifespan of hoop house plastics by covering 2-3 ft of the ends with black plastic or white plastic or 2 extra layers of clear polyethelene or any kind of tarp. This is because the ends always give out first. I surmise this is because the ends are stressed by holding the weight of the middle as well as their own weight--whereas the middle only holds its own. And reducing the sunlight's UV is the best way to extend life. (4-year plastic placed behind sheetrock or buried around foundations probably lasts 100-1,000 years.) (No need to cover the ends if you use wood frame with each section battened--as below.)
  3. Really dumb: paying several times extra for multi-layer "insulated" plastics. Especially those that require you to use a fan to blow air between layers. You can beat this simply by using 3-4 layers and crumple the plastic before putting on so the layers do not stick together.
  4. Most dumb: using fiberglass panels. They are several times more costly than polyethelene and do not last any longer than polyethelene if you follow my suggestions. The only advantage of fiberglass is that it has some rigidity for holding snow etc. But as described below you can do much better simply by placing chicken wire under the polyethelene.
  5. Not dumb IF for inner-layers only: using bubble wrap which is made for greenhouses. Sold by LittleGreenhouse.com. BUT this has no 4-year rating--it can deteriorate in 1-2 years. BUT you can multiply the lifespan by placing 4 layers of 4-yr poly on top of it. The ultimate is to use bubble wrap as the final inner layer under 4-6 layers of vinyl (see below). Or just use vinyl for south wall (photo below). And use bubble wrap for inside of ceiling and top of south wall. (Heat collects at the top and you want to keep in that heat in winter.)
  6. finished inside greenhouse with poly-n-bubble roof and vinyl wallsMy favorite insulated greenhouse roof sheathing: 4-6 layers crystal-clear vinyl separated by 1-inch-hole (maybe 1/2-in hole?) galvanized poultry fencing (chicken wire). Only get 6-mil vinyl, not 4-mil. If you build a hoop-like tunnel from pressure-treated lumber (not plastic or metal tubing) then you can use staples topped with ripped 0.75x1.5in PT strapping to hold 6 (maybe even 12?) layers of plastic separated by chicken wire. On  top of this add 2 layers un-separated US-made polyethelene with the expectation this will deteriorate and be replaced easily--meanwhile it prevents the expensive vinyl from aging or getting dirty. Please note: the chicken wire of course will not always separate two layers--but after 4-6 layers there must be air spaces created. Also please note that this also will block substantial light--even if you manage to align the holes of the fencing well. However, in winter there is little light from the ceiling. And in summer you want either to have vines or tree leaves or additional old plastic placed over the roof to reduce the intense heat. And I add to winter light and heat by using a back wall of 4-6-in studs with fiberglass insulation--covered with 3/8in PT plywood--followed by aluminum flashing to mirror the sunlight and also reduce fire hazard of a wooden wall. If you have a proper foundation then bathroom-grade sheetrock might be used instead of plywood--but my foundation is only 4-in pounded Surpak. (Just get a truckload of Surpak and hire a professional backhoe guy telling him you want same as a poured slab but using Surpak instead--he should know what to do.)
  7. For extra strength: run a bead of Lexel down the center in between each plastic layer and hitting the long side of fencing wires. This will adhere each layer of vinyl to the next and also to the chicken wire. Like papier mache, you end up with a structure many times stronger. Unlike papier mache--the vinyl is flexible and the Lexal is can be peeled off even after decades. So you can replace the vinyl 20-50 years later as needed. And meanwhile probably can walk on top of the thing. Of course, more ultimate will be to use solid acrylic as the final cover. (Acrylic is very expensive. Best price for solid acrylic seems to be whatever Home Depot has in stock--work with that instead of special ordering anything.) Important note: if you use expensive solid acrylic--then you want to add a much-cheaper and easily-replaced cover of vinyl or polyethelene to protect the acrylic from aging and scratching.
  8. Unfinished multi-use PT wood frame with some vinyl latticeTo make a pressure-treated frame: just make a 2x4 "pole shed" as if with flat roof. Then add 2 2x4's or 2x6's on edge in the center as a "ridge pole". Then rip down 1x6 PT decking into approx 1x2 or 1x3. Then bend these 2-ft OC over the ridge pole. Please note this may seem to have a weak slope. However--if you drive 1 x 2 decking screw into the 2-piece ridge pole--the arched struts then are holding up the ridge pole as much as vice-versa. Extra strapping or lattice can be added for a pergola or grape arbor. Or cover with metal roofing. Or clear plastic. Or tarp. = instant car port = breezeway = porch = shed = greenhouse = pool covering. Depending on the covering. If you avoid metal or solid coverings then you might also avoid paying year after year in extra property taxes. (Maybe. To be sure, make the covering in panels which you take down during the summer and when a tax assesor is likely to visit.) PS maybe double the 2x4's to make the corners 4x4--and/or add 3-ft or 4-ft 45-degree angle braces at every corner--because otherwise when you bend the roof slats this builds up huge pressure to bend the 2x4 posts. Well bending those posts does not spoil the structure but maybe best to avoid. Also if you use non-PT for the roof slats then you can bend it much more with less pressure--the non-PT spruce is much softer. But of course the PT yellow pine is much stronger.
  9. To make a foundation: stick 2x4 PT several feet into the ground. After first coating with liquid polycarbonate = Lexel-like in gallons for roofing. After dry, follow up with brown vinyl caulk = Phenoseal. Do not listen to teenagers who all think pressure treated wood lasts without treatment at ground level. Do listen slightly to old timers who suggest black preservative or tar--not bad but polycarbonate is much better--except to coat over with brown vinyl caulk to prevent ageing of the polycarbonate from UV exposure. Or instead of phenoseal can simply staple tarp of any color.
  10. Big caveat: pressure treated lumber is toxic! Use gloves and surgical-grade face mask, especially when ripping. My firsts PT project made me so sick I could not even touch PT with my skin. I wish it were possible to get untreated "yellow pine." Because it is mostly the wood, not the treatment, that makes PT lumber last much longer but not forever. Then--after cutting--you can simply dip or brush on  white solid stain. (One brand is really good--looks great after just one coat--ask me later to look this up.) Anyway it might last forever with plastic coatings and you might even get away with using non-PT if it is always covered. In fact my first greenhouse used non-PT and is doing fine. So I do suggest NOT using PT if possible.
  11. PS--if I build another greenhouse--I will slant the south roof 45degrees BUT have a 5-ft kneewall. My first greenhouse had a 45 slant and a 4-ft kneewall--much better sun in winter and better insulation because you can multi-layer vinyl over the trusses running from the 45-degree surface to the 35-degree opposite surface which is solid with fiberglass and coated with aluminum flashing. My newer greenhouse in photo has a high wall but not a 45-degree roof. This gives much better working space but much less winter light. So I would combine the best of both features for the best greenhouse. But above are my suggestions for an easy hoophouse-equivalent greenhouse.

 

Krystof_Huang's picture
Krystof_Huang
Status: Bronze Member (Offline)
Joined: Jan 7 2017
Posts: 25
ps about solid acrylic

Warnings about expensive solid acrylic:

  1. Remove peel-off protector soon. If left in sun it will melt on.
  2. Acrylic is brittle if it is thin. The more horizontal, the stonger it needs to be, if you depend on that strength.
  3. Even if thick, acrylic must be loosely mounted. You can pin down one side with screws. The rest must be allowed movement space or it will crack as the structure inevitably moves. Somethat like working with glass, although not as sensitive, of course. Perhaps the best is to use Lexel to glue it down--no screws through the panel itself. Or, to be safe, maybe just one screw through the center of the top side. Or of course, if you cover it with chicken wire--which is then covered with poly or vinyl film--no need to worry about gluing or screwing it down--just put the acrylic between the battens, with no screws going through it. But if it spans 3 battens then a line of screws from the center batten will be alright of course.
Krystof_Huang's picture
Krystof_Huang
Status: Bronze Member (Offline)
Joined: Jan 7 2017
Posts: 25
PPS--I meant 2-inch hole

PPS--I meant 2-inch hole poultry fencing, not 1-inch. Although I have also used 1-inch. With 1-inch the structure will be stronger but less light will get through. So it depends on the application. (1/2-inch which I wrongly mention will then not be "poultry fencing" but the much more costly and light-blocking "hardware cloth.")

mntnhousepermi's picture
mntnhousepermi
Status: Silver Member (Offline)
Joined: Feb 19 2016
Posts: 124
have you made those wood chip raised beds ?

Have you actually made and used these, or are passing on an idea ?

It would be good if we all would identify this

Anyway, if you have done this, how did do as far as soil moisture retention ?

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