Hi guys,
I just wanted to share with you this little greenhouse I have built. The idea started with having a way of keeping my Soursop alive over winter, the Sydney climate is too marginal for Soursop.
Originally I was just going to put a much larger window in our garage which faces the sun all day to keep the wind off of it so went about purchasing a used window from ebay for $30. Then it kind of snowballed into something more substantial as I read about the temperatures a Soursop would require.
It was then decided to make a small lean-to structure in front of the current window which would mean there was no need to modify the garage at all.
Some photos.
Pavers were layed for the foundations.
The frame is built with H3 pressure treated pine.
The frame was stained and then bolted to the garage, there is a layer of foam between the frame and the foundations.
The $30 window was then put in, the rest is twin wall polycarbonate.
I then put insulation batts in the rear and side wall and then lined the inside with corflute sheet sealed with metal flashing tape.
The roof is on a hinge so it can vent out the heat and there is also a door, foam is used to make the opening air tight.
The autovent opens at around 25 deg C.
Temps will drop to around 4 deg C in the early morning during mid winter for maybe 1 hour but mostly temps are closer to 8 deg C overnight. What I decided to do was place a large low profile water tank under the plants with an aquarium heater in it set to 30 deg C. It's actually an under bed storage container and its also sitting on a layer of Styrofoam.
The lid is not strong enough to support the weight of the plants so I made up a little shelf which suspends the plants slightly above the tank. I put some black plastic over it to prevent UV damage and also help the water absorb some heat form the sun.
The Soursop is very small since I grew it from seed last spring so there is plenty of space for some of my other plants which are destined to go in the garden bed just in front of the greenhouse once I finish preparing the area.
I have the Soursop in there along with a Rollinia, Achacha, Jackfruit and one of Luc's Garcinias.
We are almost in winter now down here and so far the greenhouse is around 3.5 - 4 degrees C warmer than outside during the coldest part of the night. I have temp sensors which log to sd cards for keeping an eye on the performance.
During the day if it is sunny temps peak at around 32 degrees C or about 22 if its cloudy or raining.
The roof is auto opening but I found this is not sufficient on sunny days so before leaving for work I open the bottom of the window about 4 inches which allows cool air to be drawn in as the hot air flows out the roof. I need to make something so this process is also automated, just not quiet sure how to do it yet.
This was a cloudy day.