Spring project: fixing up my old 'plastic' greenhouse

Snow is melting rapidly here above the 53rd latitude and people are itching to break out tank tops and shorts, have a drink on patios and start their outdoor projects. After a long winter with only my indoor garden to keep me busy, I used the fine weather this weekend to patch up the 14 year old greenhouse in our backyard.

Greenhouse1 We bought the 8'x6' greenhouse on clearance in the fall from Canadian Tire, thinking it might give us five years of tomatoes before we would replace it with something more permanent. It has aluminum framing and polycarbonate panels that are held onto the frames by green plastic strips that clip onto the frame. The aluminum framing looked sturdy enough, but I wasn't sure that the plastic panels would survive too long in our harsh climate, with pretty intense sunshine, extreme temperatures and wind gusts.

Greenhouse4 This greenhouse is located on the sunniest spot in our backyard (which I found using the solar pathfinder) with exposure to the west and the south. I use old trampoline netting as a shade cloth in the summer, because temperatures can easily go into the 50s Celcius without it. The greenhouse has a venting window which I leave permanently open in the summer as well.

As you can see, the polycarbonate panels have survived just fine, not a single one is broken after 14 years. But UV light on the south-facing greenhouse wall has broken down all the green plastic clips that hold the panels in place. This happened gradually and for the last five years I put some stakes into the ground right next to the greenhouse to keep the panels somewhat in place.

Greenhouse2 On this sunny Saturday, I decided to patch up the greenhouse so I could get another 5 years out of it. I bought 1"x2" and 2"x2" lumber to keep the panels in place: I sandwiched them between a layer of wood on either side, kept in place by the aluminum framing. You can easily drive a wood screw right through the polycarbonate plastic.

Greenhouse3 Since the tomatoes grew so enthusiastically in this greenhouse, their branches need a lot of support to prevent tearing. I have been using tomato cages since there wasn't anything inside the greenhouse to attach ropes to. By the time the tomato plants reached the greenhouse roof, an elaborate rig of stakes, ropes and cages was making it hard to harvest the tomatoes. Now that I have wood framing inside the greenhouse, I plan on creating wooden grow frames later this season, when the soil is a bit drier. With a grow frame surrounding the plants, it will be easy to run some wires to support all the branches.

Hopefully this greenhouse will continue to give me fresh tomatoes for the next few years. With the basil I grow inside the house, some olive oil and balsamic vinegar, they make the most delicious dish.

Update May 29 2017: I added more framing inside the greenhouse to make it easier to guide the tomatoes. Greenhouse.JPG

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