The idea of home growing your own vegetables and produce is a fantasy a lot of us entertain without ever following up on it. However, what many of us fail to realize is how easy it is to start with hydroponic growing; and even more, how simple it is for you to build your own system as opposed to buying an expensive, pre-made hydroponic greenhouse.
The process of building your own greenhouse won’t be a simple process. Not only will it require quite a bit of elbow grease, but you’ll need some spare income in order to purchase the best materials for building your greenhouse. For this DIY setup, you’ll be building a 10 foot by 12 foot greenhouse, which will be fully automated for growing plants hydroponically. It will be weather resistant as well. Once you’ve finalized the construction of your greenhouse, you will have a centralized hydroponic system capable of supporting up to forty large plants such as tomatoes, banana peppers, and bell peppers, or smaller plants in larger capacities. This greenhouse can also house roughly seventy two smaller plants as well, such as lettuce, spinach, strawberries, and other high water necessity plants.
Additionally, your greenhouse structure will be equipped with and partially automated by an Arduino based climate control system. This system works by monitoring the indoor environment through a variety of sensors installed inside of your greenhouse to measure a variety of elements such as the temperature, intensity of the light, humidity, overall C02 concentration, and the amount of UV rays received. These elements are controlled by an automated system of exhaust fans, louvre doors, heaters, grow lights, valves, pumps, and other mechanisms which respond in time with the chemistry and atmosphere of the greenhouse. You’ll be able to view the reports, analytics, and readings of these sensors through the internet, on your smart devices or on your computer in real time. You can also use third party apps to set notifications and alerts in the event your greenhouse goes above a certain temperature or has a build up of humidity or C02. Without anymore time stalling, let’s break down the process of building your hydroponic greenhouse so you can get growing!
Step 1: Getting Started and What to Consider
When you first begin constructing your greenhouse, the first thing you should consider is location in relation to sun exposure. Your greenhouse needs natural sunlight in order to maximize your yield at harvest. Try to position your greenhouse’s outline to expose it to an open section of the southern sky. Avoid objects like your home, garage, shed, fences, trees, or ditches and embankments which cast long shadows and can block out the natural light for your greenhouse.
It may also be important to consider your local zoning laws, building codes, and other associated codes. For example, some areas may require you to hold a municipal building permit in order to house your greenhouse on your land. Your local homeowner association or municipal government may also ban residents for dumping their waste nutrients from your hydroponic system. Be sure to consult your local jurisdiction regarding these laws, and be sure to inform neighbours of your intent to build in order to avoid issues.
Step 2: Preparing your Greenhouse Site
After you’ve gone through the legal red tape and decided where to place your greenhouse site, begin by painting an outline on your land covering the exact location you’d like to use. Then, dig in a trench roughly a foot wide, a foot deep, and centred on your painted lines. This trench will be important later, as it will route to your french drain that’ll run across the west side of your greenhouse. This helps to collect and dispose of excess water from snow melt and rain. It’s important to fill your greenhouse trench with crushed stone, opposed to concrete which can raise and crack if the excess water freezes. Before filling your trench however, take a prepared piece of PVC pipe. Lay it inside your channel which connects your greenhouse and trench to your Western french drain. The pipe will then connect with your drain and direct waste water and excess melt water away from collecting at the foundation of your greenhouse. Once you’ve put in your PVC system and covered it with your crushed stone, you’re ready to start creating the forms and outline of your greenhouse.
Step 3: Forming your Greenhouse
After you’ve outlined and prepared your site for a drainage system, you’ll next need to complete your concrete footing as well as the general frame of your greenhouse. Your footing will be five and a half inches tall by five and a half inches deep, this will serve as the perimeter of your greenhouse. Your outside dimensions will be ten feet two inches by fourteen feet by two inches. Your inside dimensions will measure at nine feet three inches by thirteen feet nine inches. For your framing, it’s recommended to use two by four lumber due to its strength. Your bottom wall plates are then placed on the concrete in both the inside and outside of the greenhouses perimeter.
Next, you’ll need to build the skeletal frame of your greenhouse. It will be constructed by two by six lumber, with some one by three strapping pieces of lumber to brace everything properly. Next, you’ll add in your anchor bolts and your rebar. Drill holes in each piece of your strapping and insert your anchor bolts; secure them with a washer and nut. Next, you’ll use your rebar and cut it into the shape of your anchor bolts so they can support your rebar off the ground. Double check your measurements and ensure everything is sturdy.
Step 4: Pour your Concrete
This step takes a bit of time and can be frustrating for some who are new to DIY. Unless you have a team to assist with mixing your concrete; you will need to mix three hundred litres of concrete by hand. Using store bought bags of cement of your preference, prepare your cement as one part bagged cement, two parts sand, and three parks of crushed stone leftover from your initial trench work. Next, after you’ve prepared your concrete; pour it into the frame of your greenhouse evenly and smooth the top over to prevent air bubbles. Monitor the drying of your concrete, checking quarterly on the hour to make sure it is setting well.
Step 5: Framing, Building your Walls
After the effort of mixing your cement, this next step is a bit simpler. You’re going to need to build your walls with a bottom plate that’s pressure treated and a spruce top plate for additional support. Your walls will be eighty one inches tall with studs spaced about every two feet. Your framed walls should be about seven feet tall in total height, your two fourteen foot long walls spaced and studded in the same manner. Drill holes in the bottom plates of your walls and secure them into place with anchor bolts and nut screws into your lumber foundation. Nail at key points for additional support, and begin adding a second double top plate to begin the process of adding your roofing.
Step 6: Building your Roof, Installing the Purlins
Next, you’re going to need to construct your roof. Begin by building a ridged pole which is fourteen feet long out of a piece of two by six. Then, add on your rafters with pieces of two by four. Be sure to space these rafters by two feet and secure them into the ridge pole on the top and the wall’s top plate area. Next, insert a half inch strip of plywood along each side of the ridges, with another same size strip of plywood running along the bottom edge for the sides of your roof. This holds your roofing square and is the attachment point for your glazing.
Next, you’ll dress your roof and walls in purlins. These are built out of eight foot long pieces of two by six lumber which are then broken down into three quarter of an inch strips. This is cheaper than purchasing your strapping from the store. Add in corner braces to each corner of all four walls until you have sixteen total. This keeps your structures stiff and square, and the ridge pole will provide support for the diagonal braces to hold your roof steady.
Step 7: Creating your Door, Exhaust Openings
After you’ve built the frame for your roof and purlins, you need to modify your frame somewhat in order to create your door frame and sections for your exhaust fans. Create your openings by trimming the edges with the one and a half inch three quarters inch strapping you previously used for your purlins. This ensures your edges for your glazing will be secured into the trim of the greenhouse.
Step 8: Screening and Glazing your Greenhouse
The final and most important step of building your greenhouse is adding in your glazing. Your glazing material should be an eight millimetre twin wall poly carbonate panel. They have specific cells inside of them which contain small pockets of air and provide a good degree of thermal insulation for your greenhouse. Additionally, the poly-carbonate material for your glazing is twenty five times stronger than glass and five times stronger than acrylic. It is built with the strength to withstand hailstones and golf ball sized objects raining against it. Secure your glazing in place with your nail gun, being careful not to crack, shatter, or damage the poly carbon twin walls.
From there, your greenhouse is properly insulated and you can begin to install your hydroponic systems inside of your greenhouse. We’ll cover the construction and various types of hydroponic systems in a secondary article. For now, get your tools together and get building! Your dream greenhouse awaits you.
