News and commentary about ecodesign, geothermal heatstorage, PAH seasonal storage, urban farming, rainwater harvesting, grey water recycling, natural ventilation, passive summer cooling, energy autonomy, off grid solar comfort, as well as refined prototypes i am currently building.
Wednesday, October 15, 2014
How to build My 50 Dollar Greenhouse » The Door Garden
The planning is over and construction on my hoop house greenhouse has begun. I’ve rounded up all of the materials and it looks like I’m going to end up with about $50 in a 165 square ft. green house. Granted I already had most of the materials because I’m an incorrigible pack rat, but even if I had bought everything new just for this polytunnel It would still only come to about $120 $150 – less than a dollar per square ft. Due to the fact that we are in the midst of a global economic meltdown, and the future is a bit uncertain keeping the cost of this project as low as possible is an important consideration.
After some research I’ve decided to build the structure of the hoop house out of 20 ft. joints of three quarter inch PVC plumbing pipe. Some similar greenhouse designs that I’ve run across use 10 ft joints of pipe and then fasten everything together with pipe fittings, but I’m saving quite a bit of cash with the long joints of pipe and by not using any fittings – also overall simplicity is improved. There is one thing though, you can carry 10 ft joints of pipe in the mini van, but hauling 20′ pipe requires a truck and preferably a ladder rack. However, you could just cut them in half right at the home improvement store and then put them back together when you get home with the coupling that is built into one end of the 20′ long pipe joints – 10′ pipe joints don’t have the built in couplers – just go to the home improvement store prepared with a saw or pipe cutter.
My hoop house green house is going to be 11 feet wide and 15 feet long, and will be about seven and a half feet tall in the center. You could make one of these as long or as short as you want, but using this design the width needs to be between 10-12 feet. 11 feet wide just happpened to work out with the layout of my garden which has 3 foot wide beds with 5 ft paths between (the wide paths are so that I can keep it tidy with my riding lawn mower) so eleven feet covers two beds and the path between them. This width also makes the sides go fairly straight up from the ground for the first few feet – I’ve noticed that in some hoop house / polytunnel designs the outer edges are almost unusable because of the slope of the greenhouse sides.
If your Greenhouse is too Flat it will collapse!
You might be tempted to make your greenhouse wider and lower at this point to get more floor space out of it – but be careful. If you have snow in your area it will slide off of a high peak a lot better than it will if your greenhouse has more of a flattened shape – and the same goes for heavy rains. If your hoop house shape is too flattened it will cave in the first time it snows or rains really hard!
How to Build the $50 Hoop House
I decided to begin the construction by building the end walls first – even though it would be more fun to throw up the main structure in just an hour or so and make a big showing of progress, I think that in the long run it will be quicker and easier to build the end frames first on my garage floor.