Experiment 5
Upcycled Backyard Greenhouse
Upcycling is a great way to transform otherwise underutilized materials into a means to produce food. While only limited by the imagination, the possibilities are nearly endless. Experiment 5 demonstrates one possibility of an unused carport structure being transformed into a backyard hydroponic greenhouse using simple construction materials.
Step 1:
Gather the following materials and tools:
Materials
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Tube-frame carport (or some alternative)
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General lumber (2"x3" and/or 2"x4") for the framing
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Pressure-treated lumber for the wood sill plate (which the bottom of the structure gets fastened to)
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Construction Screws and washers
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UV-resistant polyethylene film for greenhouses
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Ground anchors
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Bolts and washers (to screw into ground anchors)
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Gravel and cement (to make concrete)
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1/4" Lag screws and washers
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Corrugated Polycarbonate Roof Panels
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Corrugate panel closure strips (foam gaskets optional)
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Piano/door hinges
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Intake and exhaust fans with temperature controller
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Patio stones
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Tarp or gravel for floor base
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Shade cloth (full depth of greenhouse)
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Bungie cables and/or rope
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Two beeswax automatic window/vent openers
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Clear exterior caulk
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Tools
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Mitter saw and/or Circular saw
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Drill and drill bits
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Bucket and stick/ mixing paddle drill bit
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Tape measure
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Pencil/marker
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Shovel
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Speed square and/or T-square
Step 2:
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Remove existing tarp covering and accessories.
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Unfasten tub frame from base if existing
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If structure is moving, locate so it get at least 6 to 8 hours of full sunlight per day in the warmer months.
Step 3 :
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Lay down patio stones along edge of the greenhouse walls.
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Dig three holes minimum on each side for ground anchors.
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Ensure hole is the right height so a least 150 to 200mm (6" to 8") of stone/cement (concrete) mixture is below the bottom of the ground anchor.
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Fill hole with gravel and set in ground anchors to the correct height. The top of the ground anchor should be below the wood sill plate and adjust according to your bolt length.
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Remove ground anchors and prepare for cement pouring.
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Step 4:
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Fill the hole with your cement mixture. While pouring in small batches, mix the cement in with the gravel to get them incorporated.
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Once the gravel and cement are mixed together, set in the ground anchor to the correct height.
Step 5:
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Drill holes in the wood sill plate to match the location of the ground anchors. Ensure the holes are not wider than the bolt and washers.
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Set wood sill onto patio stones.
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Predrill holes at each tube frame footing for lag screws
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Move tube frame onto wood sill plate and lag screw down to plate.
Step 6:
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Start framing in front of greenhouse. The layout is dependent on your tube framing. In general, you want a door that's at least 36" wide so large barrels and equipment can be brought into the greenhouse.
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Predrill all holes required through metal tubing using the appropriate metal drill bits for the screw sizes.
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Ensure cross bracing is provide by inserting diagonal framing members where ever possible. This will help stabilize the greenhouse and prevent it from blowing over.
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Install the door using piano or door hinges. Leave space for an air intake fan along the front face of the greenhouse.
Step 7:
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Measure and prepare two skylight air vents. This is best built on the ground and lifted into place.
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Build and outter frame to fit in between the spacing of the tube framing
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Using piano or door hinges, create an operable centre panel vent.
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Fasten corrugate plastic panels to operable vent. Predrill all wholes and use rubber and metal washers to prevent cracking the plastic.
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Create an interior lip stop to prevent the vent from swinging inwards.
Step 8:
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Predrill holes through metal tubing.
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Mount vent frame to tube frame, ensuring everything remains squared off.
Step 9:
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Once all of the framing is complete, measure and cut the polyethylene film to the required size.
- Start by fastening one side of the poly film to the wood sill plate using a wood strip to keep it secure.
- Stretch the poly film over the tube structure, ensuring it does not catch on anything which could tear it. The film should be as taught as possible. Fasten other side to the wood sill plate using wood stripping.
Step 10:
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Measure and cut the poly film for the two open ends.
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Stretch and fasten poly film to wood framing and sill plate. Wood strips should be provided at all wood members.
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Cut out poly at door and any fan doors.
Step 11:
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Cut out poly film around operable vent. Ensure there is an adequate overlap over the hinges to allow for the flow of water.
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Using exterior grade clear caulk, adhere the poly film to the corrugated plastic sheet.
Step 12:
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Install vents and front and back of greenhouse. The goal is to bring cooler air (low) in and vent out the hot air (high up). In the example a shop fan was used for the intake which required an extra operable door. For the exhaust fan, a commercial fan with louvers was used. This option is highly recommend as it makes the whole process simpler.
Step 13:
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Provide power to the greenhouse through whatever means meets your local electrical code.
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Setup the thermal controller for the fans to ensure sustained temperatures do not exceed 30 degrees Celsius. (note that on the occasions where ambient temperatures go above 30 degrees, you just do your best at keeping the greenhouse cool)
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Install the shade cloth in the summer months when temperatures are really hot.
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Start spatial planning on what methods and systems you want to use in the greenhouse.
Step 14:
Enjoy extending your growing seasons throughout spring and winter months. Remember to experiment with different types of hydroponics and other growing methods to see what works best for you.