The Hydroponic, Automated, Networking, Climate Controlled Greenhouse Project: Construction

This Instructable will cover the construction of my Hydroponic, Automated, Networking, Climate Controlled Greenhouse Project. The construction phase of the project covers the concrete footings, the framing and the glazing of the greenhouse.

Other Instructables that cover elements of the "Hydroponic, Automated, Networking, Climate Controlled Greenhouse Project" are listed below with many more to come:

Part 1: The Construction of the Greenhouse
Part 2: The 72 Plant Vertical Garden

The greenhouse when completed should be equipped with a large, centralized hydroponics system capable of supporting up to 40 large plants (tomatoes, bell peppers, banana peppers, etc.) and up to 72 small plants (lettuce, spinach, strawberries, etc.) for a total of up to 112 plants. The greenhouse will be equiped with an arduino based climate control system capeable of monitoring the indoor environment through a variety of sensors (temperature, light intensity, humidity, CO2 concentration, etc.) and automaticly adjusting each variable by controlling different devices (exhaust fans, louvre doors, heaters, grow lights, solenoid valves, pumps, etc.). The readings from all the sensors as well as the on/off status of all of the devices should be sent out over the internet and be viewed remotely and in real time from any computer or mobile phone.

As of this moment the greenhouse's skeleton is all that is completed. I didn't get as much done over the summer as I had hoped because of the nasty weather. However, over the winter I am working on constructing most of the hardware to go inside the greenhouse including the climate control system. I hope to be up and running by the time it's warm enough to start growing.

Each major section of this project should be it's own instructable and when it's all finished I'll compile it into a guide. For now I'll show you how I went from patch of land to a greenhouse skeleton.

Step 1 Considerations to Make Before Starting

I would venture to say that the single most important thing to consider when choosing a site for a greenhouse is sun exposure. A greenhouse should get as much sunlight as possible and in order to accomplish that it should be exposed to the open southern sky. Large objects on your property such as your house, a garage, a tool shed, fences, trees and embankments tend to cast long shadows on their north side and you don't want your greenhouse in any of them. This isn't much of a problem in the summer months or at low lattitudes but at high lattitudes in the fall, winter and spring this effect is quite profound. For instance, I live at 48 degrees North latitude and on a sunny winter's day my house casts a shadow almost all the way across the street.

In my particular case I got lucky because my backyard is totally southern exposed. The rear wall of my house faces almost perfectly south. It's only off by about 7 degrees to the east. I knew that I wanted to have both a garage and a greenhouse and my backyard is too narrow to put them both side by side. Even if I could put them side by side, the greenhouse would be in the shade of the garage either in the morning or in the evening, depending on which side it's on. So my solution was to put the greenhouse behind the garage.

The first picture is taken from an upstairs window looking south out over the backyard. The large orange rectangle closest to the camera is the site for the garage while the smaller rectangle out farther to the south is the greenhouse. The second picture is an "after" shot from the same location to clarify the meaning of the first picture.

You should also think about your local laws and building codes. In my municipality a building permit was required for my greenhouse and I had to follow a number of rules such as a 1.5 meter variance, a maximim size of 33% of my backyard and to keep it behind my building line (it has to be behind my house, not in front) to name a few. If you want a hydroponics system you may have to dump waste nutrient solution into the ground from time to time. Your town may forbid this, especially if there are drinking water wells nearby. You may also be required to let all of your neighbors know in advance and you might not be able to build if any of them have any objections. You should find out all of this in advance before you build because if you violate any municipal laws you'll probably be forced to tear it down and pay a fine.

Comments

[Indegreen]

Nice clean job! One other easy item is to add at least 2 rafter ties. They are horizontal 2x4s attached from one rafter to the opposite side at about halfway up from the top of the top plate to the ridge. They are simple, but important bracing to keep the center of the greenhouse from spreading out, or "caving in". You can cut and paint them on the ground, or indoors, and then install them and touch up the nails. Even just one tie would do a lot.

[static]

As it ran in my mind what you describe are more often called collar ties, I did a search and located http://www.nachi.org/collar-rafter-ties.htm . from that page;

Collar Ties
collar rafter tie
Collar ties are designed to tie together the tops of opposing rafters. This helps brace the roof framing against uplift caused by wind. Collar ties must be placed in the upper third of the roof.

• Collar ties, contrary to popular belief, do not prevent walls from spreading. 

 

Rafter Ties

 

Rafter ties are designed to tie together the bottoms of opposing rafters. This helps keep walls from spreading due to the weight of the roof. When the walls spread, the ridge will sag. A sagging ridge is one clue that the home may lack adequate rafter ties. Rafter ties form the bottom chord of a simple triangular roof truss. They should be placed as low as possible in the roof framing.

Personally I really never knew what their "official" purpose was. until now. Thanks to your comment now I do, along with a web site I can search for other items.
 

[LancePenney]

Thanks. I had a plan to use some steel aircraft cable together with the appropriate rigging and turnbuclkes. That way it wouldn't block out as much sunlight and I can turn the turnbucles whenever I need to draw the two sides of the greenhouse together.

[winterwindarts]

Cable will only hold up to tension (spreading out) and not compression (caving in). At 48degN you need to be concerned with both wind and snow which usually exert a large amount of compression. You really should use a rigid material for the rafter ties. Sunlight getting through is important so metal-especially steel-is a good choice so instead of cable look for u-channel, hollow square, or angle stock (flat pieces are likely to bend). Copper and aluminum are too likely to bend or stretch so try to avoid them if possible especially where snow is an issue. Another option is *rigid* metal conduit meant to safely bury electrical wires-I've known several people who have used them successfully for the ties in various greenhouses in the northern US although the connections can be tricky since conduit doesn't normally have any flat sides.

If cables are all that you can find, instead of putting them straight across like the rafters are, put them diagonally from corner to corner in pairs so that they form an X. It's not perfect and will still be susceptible to compression but it shouldn't be quite so bad and the frame is more likely to stay square. Structural cables are really meant to be placed diagonally and are just to keep walls/frames square and plumb. When used in pairs they make a loosely framed wall much more rigid and better than nothing but again, they won't help with the compression such as from wind or snow.

Sorry about the long winded reply but I've seen a few too many structures supposedly reinforced by cables that still collapse from snow load or a good windstorm.

[LancePenney]

The plan was to put the cable on the two long walls that are not the gable end walls (I dont know what you call them). If the cable were to run from top plate to top plate then any compression on the roof would translate to tension on the cable.
However, I have two pepole now who seem to know what they're talking about telling me I should use rafter ties. Perhaps I will use ties but I will install the cable first and use the turnbuckles to draw the two walls together and hold them in place while I install the ties.
As for the rest of the structure, the corner braces on the walls should be enough to hold everything stiff. It cant be any worse than the 7/16 OSB (or "Cornflake Board") they use for houses these days.
Thank you for all your advice, both you and "Indegreen"

[winterwindarts]

I'm not sure what running the cables along the top plate of the non gable walls would accomplish, unless the top plate is pieced and it's pulling apart with no load. The compression on the roof would create tension in the direction of the top plate of the *gable* walls but the compression would just result in a downward force on the non gable walls-not tension along the top plate. Things change when you take wind into account but the non gable walls still don't experience much tension structurally.

Push straight down on an upright pole and you aren't going to do much other than sink it deeper into the ground. Push straight down on the top joint of an A frame without a horizontal cross piece to hold the legs in place (so really an upside down V) and it's going to collapse as the legs spread out.

Triangles are only more sturdy than a rectangle if all three sides are attached to each other, remove one of the sides and it fails which is the reason for using rafter ties.

The frame of your greenhouse is already looking much more secure than most, especially with the crosspieces in the corners of all the walls. A lot of people buy kits with metal frames that bend a bit too easily (including me) with joints that aren't as secure as they should be and have to spend a lot of time jury rigging repairs or see everything come crashing down.

[LancePenney]

The cable I was proposing would run from one leg of the upside down V frame to the other leg of the a frame. When you push down on the top joint of the V frame, the cable would prevent the two legs from spreading out and collapsing. It would also prevent the downward force on the V frame from spreading apart the two non-gable end walls. So weather the cable or rafter tie (doesnt matter which one) is attached between the legs of the A frame or attached between opposite non-gable end walls, the dynamics of the entire system are the same and a downward force on the roof does not translate to lateral force. The only difference is that the rafter ties make the structure look like an A and the cable between the top plates make the structure look like a triangle. If you were to use a piece of wood in place of my proposed cable placement, you would essentialy have the bottom cord of a truss which we all know is structurally sound.

[bpark1000]

If you are trying to extend your season more, consider 5 layer polycarbonate glazing. It has thick layers inside and outside, and 3 thin intermediate layers. Remember that polycarbonate sheet made for greenhouses has a co-extruded UV absorber on one side only.  If you put it up backwards, it will be degraded quickly!  Usually the UV-protected side is coated with a light blue plastic protective sheeting.  After cutting to size, peel the blue sheeting off only around the edges, then install.  After everything is done, you can double-check that all the panels are facing correctly (blue film to the outside) before peeling off the film.  (Beware when cutting triangle shaped pieces that are not mirror symmetrical, that you cut them properly so the blue faces out!)

Do not stack polycarbonate panels on the ground in the sun!  The heat can accumulate amongst the panels and melt them!  Cover them up or place on the ground one layer only.

[mrcurlywhirly]

Nice work Lance, and a detailed set of photos.

We are interested in erecting a very similar type of greenhouse, using an arduino controlled automated watering system. I have seen a simple controller setup on this site.

Will follow your progress, particularly how the carbonate sheeting stands up to punishment. Hale can be a problem where we live (sub tropical Queensland), sometimes biggier than golf balls...
I have plenty of toughened glass for the sides, was looking for something more resilient for the roof, so that may be the answer.

[cblair1]

Thank you so much for this wonderful project! I really wanted to thank you for the great information about permits, rules and regulations!!!! These are often forgot about!! I look forward to following this project, I live almost on a Great Lake, so I am not sure I can built this unless I can some how figure out where to put my waste water without it going into the ground, this would be a big NO NO and huge fines in my location. Thanks again!

[85rocco]

I've built a couple of greenhouses and learned from my mistakes; there are a few special considerations in greenhouse design that many inexperienced builders overlook, if you design it like you would a garden shed only with clear glazing, you're going to have problems. The most critical factor to consider is control of condensation, under certain weather conditions, there will be a LOT of condensation formed on the glazing, you need to make sure that all that water has somewhere to go, if for example, it collects on the top or bottom plate of the wall or in the soffits, you'll quickly get mold and mildew problems, wood rotting etc. designing away as many of those flat horizontal surfaces as possible will pay dividends in the long run. Along those same lines, use a good quality, mildew resistant paint. Also, design in as much ventilation as you can, it's almost impossible to have too much and make sure some of it is useable when it's raining.

[Ricardo Furioso]

Lovely work.
We do want to see how she turns out.
If you could explain a bit more about the polycarbonate sheeting and where you got it and how you install it, that would be good.
Thanks.
rf

[LancePenney]

Thank you. I will be sure to provide much detail on the installation of the polycarbonate panels when I am able to. I got the panels from a company called "Harnois" that are based in Quebec I believe. I found a local distributor here in St. John's and they shipped them in from Toronto.

[wallerps]

Lance, I'd like to thank you as well for putting this up. I've been thinking of doing something like this for a while and seeing your design has encouraged me to go ahead and get it started. I have a very sloping yard so I will do a lot more foundation work than your project, but renting a cement mixer is the way to go for sure. I look forward to seeing the finished product when you get a chance to finish it.

Happy New Year, from Sparkie in Quinton Alabama

[The Reverend]

Thank you for this comprehensive and clear Instructable!

[miguipda]

Hi,

a real interesting project. Please do not forget to precise the code used with your arduino (networking project).

For information I found this arduino (supported code) with already more specification that the original arduino (for the same price) :
http://www.freetronics.com/products/etherten

This self sufficient arduino is also a need to reduce cost :
http://www.instructables.com/id/Self-Sufficient-Arduino-Board/?ALLSTEPS

A moisture control is also interesting :
http://www.instructables.com/id/Garduino-Gardening-Arduino/step4/Build-Your-Moisture-Sensor/

To manage a watering controller :
http://www.instructables.com/id/A-watering-controller-that-can-be-home-networked/

And this could also interesting you :
http://www.instructables.com/id/Backyard-Automated-Greenhouse/
http://www.instructables.com/id/Garduino-Gardening-Arduino/

Then I will stay tuned to your project because I hope be able to do the same.

I wish you a Happy New Year.

Miguipda ;-)

[drbill]

Why are the footings on the surface?
Why do they not go into a trench as a foundation is usually built?

[LancePenney]

Once the area around the greenhouse is landscaped, the footings will be backfilled right to the top with topsoil and that way it will kind of be in a trench.

[wierdguy03]

i was planning on making an instructable similar to this in the next couple months, but now i guess i won't since you provided very good explanations for everything, very good thus far.

[CementTruck]

Do it anyway. Yuu might have some variations that would be helpful for someone.

[dionysus.god]

Thank you for putting this up. I really like your thorough process on erecting the frame. When I get somewhere where we're not renting a house, I'll be sure to use these methods to make mine. Hope to see your hydroponic system by then too! =D