Open Source Greenhouse Project

My goal is to organize a guide or resource for making your own greenhouses for low cost. If anyone has ideas to contribute please post. I was looking to buy a greenhouse, and even for fairly small ones, a greenhouse could cost easily $600+ and that is just for parts, you still have to assemble it yourself.

The idea I have been working on consist of rebar pieces about 2 feet in the ground for the greenhouse foundation, then putting 1/2" pvc on top of them, making a frame, then finally putting a greenhouse plastic film over the pvc, secured by pvc clamps. Here are some photos of the current project I am working on, I have fairly high winds in my area, and nighttime temperature can go below freezing this time of year, although it doesn't snow at 32 latitude. The winds have been the biggest challenge so far, I had to do several last minute redesigns, and I still am not finished, but I have the best working model so far. You can see in the pictures the frame and plastic partially covering it (didn't put it over yet). Also, you can see the rebar pieces I put in the ground, some of the PVC fittings and other ideas of how it works. The size is approximately 30 feet wide, 30 feet long, and 8 feet at the highest point tall. The total cost for this so far is probably under $150 for the frame alone!




The equipment used besides that materials are, a pvc cutter, a ladder, a hammer to drive the rebar into the ground, measure to cut pvc lengths, and thats about it.

Here's a link to the basic hoop house design I'm modifying. I like the idea of the PVC stake "sleeve" for the hoops, but I'm pounding a piece of #3 or 4 bar and then slipping the PVC over that. Still working on an improved end design.

http://westsidegardener.com/howto/hoophouse.html

Great idea to do a thread on "how to".

hi Mountaingarden. Thanks for the reply, I have seen that site you linked to, actually that was partially what my original idea came from. However, I am looking for an expandable design that would allow for custom sizes specifically much wider design (30feet). The setback of the design in the one listed is the width is only 10 feet, and a portion of the sides is sloped PVC and won't have the full height to work with.

btw, here is a link to the snap clips I am using, so far they are really great, although when the wind kicks up they can pop off in very volatile positions.
http://flexpvc.com/cart/agora.cgi?product=PVC-Snap-Clamps

After doing this first one, I already have ideas on where I went wrong and what I would do differently. I think in the future I would put reinforcements at every 5 feet interval. PVC is really cheap so it doesn't hurt to use a lot of it.

In the link of the hoophouse that you poster before, is she using straight 1/2 pvc to secure them into the ground? I don't know how she would insert the pvc into the ground. maybe i missed something

squarepush3r said:

hi Mountaingarden. Thanks for the reply, I have seen that site you linked to, actually that was partially what my original idea came from. However, I am looking for an expandable design that would allow for custom sizes specifically much wider design (30feet). The setback of the design in the one listed is the width is only 10 feet, and a portion of the sides is sloped PVC and won't have the full height to work with.

btw, here is a link to the snap clips I am using, so far they are really great, although when the wind kicks up they can pop off in very volatile positions.
http://flexpvc.com/cart/agora.cgi?product=PVC-Snap-Clamps

After doing this first one, I already have ideas on where I went wrong and what I would do differently. I think in the future I would put reinforcements at every 5 feet interval. PVC is really cheap so it doesn't hurt to use a lot of it.

In the link of the hoophouse that you poster before, is she using straight 1/2 pvc to secure them into the ground? I don't know how she would insert the pvc into the ground. maybe i missed something

Click to expand...

One of the modifications I'm considering is doubling the size (20 foot sticks) , with purlins at 10' using 4-ways. I will be doing my hoops 2 feet o.c., for have both wind live loads and snow dead loads. As you said, pvc is cheap.

Agree with you on the PVC stakes, which is why I plan to use an inner piece of #3 rebar, then bury the pvc piece perhaps 12" below grade, because I think it would make a snugger "sleeve" for the hoop than plain rebar.

Along the sides, to help with wind lift, I'm going to use a continuous piece of 1x6 (buried about 3") with 20" pieces bolted between the hoops on the inside.

Height is still an issue, but since I'm short, easier to do some sort of lst on either side, trees down the center....limited to 15 plants, so should have plenty of room.

What type of plastic are you using as an outside barrier? Also, do you have any suggestions on how to make it air tight?

Costco Carport

I'd string several Costco carports together.
I've been using them for years the frames are stout in the wind. We've had very high winds & the worst that happened was the plastic tore loose on 1 side. Easy to fix.
They work very well
Links to my carport grows below
Good luck

peace
doublejj

Micobfsb said:

What type of plastic are you using as an outside barrier? Also, do you have any suggestions on how to make it air tight?

Click to expand...

greenhouse plastic film. Depending on how air tight you want it, but to do that you would extend the film outwards several feet, and place wood on top of it to keep it on the ground. Use clips and you could make it fairly secure, but airtight like 100% sealed would be fairly difficult for a greenhouse.

doublejj said:

Costco Carport

I'd string several Costco carports together.
I've been using them for years the frames are stout in the wind. We've had very high winds & the worst that happened was the plastic tore loose on 1 side. Easy to fix.
They work very well
Links to my carport grows below
Good luck

peace
doublejj

Click to expand...

That's exactly what I'd do, but already have almost all the parts for a hoophouse in my "construction boneyard". Decades in construction means an incredible amount of leftovers. (To date myself, we used to call it "seeds & stems"...lol) Have the pvc, cedar, rebar, all fasteners and most of the fittings. The cost of the cover is the only real $$, plus cleans up yet another pile of keen junk! Also scored over 30 pieces of 44x77" laminated and tempered glass. Half are walls in a glass room on the house, but the rest will eventually be a greenhouse w/shade cloth. Now that I'm "retired", time for all those projects I never had time to tackle.

Does anyone have any specs for the price and size of the Costco carport? They don't seem to list it on their website and my local costco doesn't carry it.

squarepush3r said:

Does anyone have any specs for the price and size of the Costco carport? They don't seem to list it on their website and my local costco doesn't carry it.

Click to expand...

Think they're about 10x20, 10 feet high, and around $250 here. DoubleJJ has made some smart modifications. Clothesline "rafters" and stilts to raise it several feet in the ground! His thread has great pics. If your local Costco doesn't carry them (they might just be out), freight could be dear.

All Costco have them, they are a seasonal item. They will be there soon. They are $199 here. They come complete with a cover. You only need the frame.
Check my grow threads below for more info

peace
doublejj
P.S. Try craigslist

just wanted to update, my design does not work. I came today after a rain and it was all knocked over almost. Back to square 1, maybe I will try a design more like the westsidegardner article above

Someone here on RIU just got a carport frame off craigslist for $15!

peace
doublejj

ok, I checked craigslist, and their carports I found one for like $199 10x20. I don't think I could fit it in my car though, and its a bit pricey. Scoring on a carport for $15 is one thing, but full prices of several hundred is another, and definitely adds up.

Like I said, my old plan failed, but I got a new plan now after I talked with some folks who gave me some suggestion. The new idea, is to take concrete cinderblocks, put the rebar inside and set it with concrete. This will make the rebar fused with the concrete, then bury the concrete about 1 foot just so the top of the cinderblock is covered. This will provide a much heavier and sturdy structure I believe to tolerate high winds and stress, to put the PVC over.

Will let everyone know how it goes!

STOP.....
Listen to Doublejj....Dude is old skool and lives a "been there, done that" type of life...
He knows his shit.
Your chasing your tail now.
Roll a couple joints, click on his thread, read and learn, it's all right there, everything you need to know.

He's like E.F. Hutton, when he speaks people listen!
TMB-

treemansbuds said:

STOP.....
Listen to Doublejj....Dude is old skool and lives a "been there, done that" type of life...
He knows his shit.
Your chasing your tail now.
Roll a couple joints, click on his thread, read and learn, it's all right there, everything you need to know.

He's like E.F. Hutton, when he speaks people listen!
TMB-

Click to expand...

Hey treeman. I've been following JJ's carport greenhouses for a few years now. I have been very impressed with his project, and it served partially for the inspiration to do my project. Carports as I mentioned run several hundred dollars though. If you can get a used one for cheap, then that's great, but local ones in craigslist are $199 for 10x20 when I checked recently. Also, if you want a size different than a carport size, then you will have to customize it anyways.

So this guide is more for making custom sizes for a fairly low cost.

Keep watching craigslist, people sell the frames all the time. You should be able to buy several before spring planting
ABM just bought a carport frame for $15, they're out there, keep looking

peace
doublejj

If your a construction guy with a bunch of material left laying around check this site out,geodesicgreenhouse.org for plans.
Also make sure you check out growingspaces.com to see what people in colorado are doing with fruits and veggies in them,im really surprised there have been no threads about cannibis in one yet,they work exceedingly well in inclement weather and high wind areas.
double j's carport greenhouse is pure genius but doesnt fly(well actually it does!)in my area due to high winds,20-40 with gusts to 70+,Also we get huge temp swings it can be 80-90 during the day and 35-40 at night,todays high was 84 and i was riding my harley in a t shirt and it will be in the 30's tonight!

squarepush3r said:

just wanted to update, my design does not work. I came today after a rain and it was all knocked over almost. Back to square 1, maybe I will try a design more like the westsidegardner article above

Click to expand...

Sorry to hear. I was afraid your spans were too ambitious, even for SoCal. If you put your rafters/purlins/hoops/whatever more than 2'0" o.c., you need to beef up their size. More of smaller dimension is cheaper. Likewise, bending longer is cheaper than fittings, which puts hoop houses in the cheap seats. In that event, the stronger the pipe, the more rigid...so you'll need more to make it stronger for a cheap price.

Your design was a hybrid between a hoophouse and a carport frame, and needed both extra rafters and more purlins. For it to be successful, it would be far more expensive than a Costco frame. In a larger size, that would be a good shape, but it's expensive because it would need much larger components to work in dead or live load situations.

In San Diego, you don't have dead load issues (snow), but live loads (wind, rain) took you out. If you're on a budget and can't find a fantastic Craig's List score, I'd consider a hoop house. I'm at schematic design of a prototype with a rebar anchor, sleeved hoop system, a maximum of 2'0" o.c. PVC is $1.18/stick up here, so $2.36 per hoop. Fittings are the costly part, between $.50 and $2.50/each, so budget about $10 total per hoop. Covering is where you can do it cheap for a year and then upgrade (my plan...right now...tonight...unless a greenhouse carpenter fairy magically appears) subsequently.

But, a few more hoops is cheap insurance things won't fall down and go boom at a real horrible time. You can't unring the bell of broken limbs in August because you didn't spent ten bucks in April. (That's the lesson I learned last year with rain and mold and not having the time to slam a hoop house in!)

Obviously construction paid the bills for a long time...while better can be the enemy of good enough, bugs me when there's not enough time or money to do it right and then you have to do it over at twice the time and twice the cost. Hope you learn something from my mistakes! cheers, mg

ps re-reading this post reminded me of a final exam projects in a structures class in college... We were divided into teams and challenged to build the largest geodesic dome we could, using plastic drinking straws. (dating myself....department chair had been a fellow of Buckminster Fuller). Each team of 10 divided into 2 groups....one to assemble panels and the other to steal straws.

Seriously...an entire class of structural engineering students descended on the local bars and stole every plastic straw they could get their hands on!!! I was on the assembly team, so didn't risk arrest, but can still close my eyes and visualize fastening straws together with sewing pins and pliers. lol... I'm stoned and remembering. Learned a lot from that. Ours failed. Tried to make it too big and needed apple boxes filled with rocks to keep it from falling in on itself! Got a B, but only because the wind didn't kick up.

squarepush3r said:

just wanted to update, my design does not work. I came today after a rain and it was all knocked over almost. Back to square 1, maybe I will try a design more like the westsidegardner article above

Click to expand...

I was looking at your original post and was struck by the similarity to what I built last year. It too was ruined by high winds and rain.
What went wrong:
1: I used the thinner walled 3/4 inch pvc instead of the sc 40, I was being cheap. Might even have been better to use 1 inch pvc.
2: I didnt take into account the weight of the plastic tarp, which caused the roof to buckel, I braced these up with posts but the combination of weight and flimsy pvc caused to much stress, and several joints broke due to the wind.
3: Although everything was anchord securely, and lightweight rope used to tie everything down, the wind still found the weakest part of the structure, and once that was loosened, everything else went to hell.

On to plan 'B', whatever that is.