I call this my solar greenhouse because it makes the best use of low southern sun during the winter. The building has a deliberate orientation of east and west. Even though all greenhouses make use of solar energy, this project is a long one and intended to be my cold storage location for freshly matured plants that I'm going to take into the winter months with no additional heat.
Another built from scratch project, here is the third greenhouse in our fleet of homemade greenhouses. Although still under construction, we are planting some of the beds now as the only items left to install are the ends and the ripstop poly cover. Since the central walkway and between bed walkways are generous, there should be no problem finishing the construction while getting the garden going.
This homemade greenhouse is a Quonset hut style made from chain link fencing top rail. As you can see in the photo below, bracing a structure this size is a little more involved than simply throwing up some hoops.
If the building is narrow and not so tall, it's much easier to build it strong without so much bracing. The wider and longer you make it, the more challenging it is because it starts to test the limits of chain link fencing top rail as the main structural element.
The building is secured to the ground with stakes and
will have many hold-down mechanisms on each side connected to “dead
men” buried deep on each side of the structure. I'm also going to incorporate some "ends" inside the structure for better shell strength and as a means to hold the structure in place.
The building will be held in place on the foundation stakes so that the wind doesn’t have a chance to push or lift it. This will also minimize vibration of the building and its foundation. The idea here is to build it to withstand 100 mph winds because we get 70 to 80 mph winds several times a year, and 40 to 60 mph winds are not uncommon.
If you are serious about building a large solar greenhouse, the Quonset hut style is my suggestion. It is naturally strong by its shape, and you can build it one "rib" at a time instead of constructing separate walls and rafters.
Building a solar greenhouse like this requires that you have a tubing bender such as the one shown below. Although I had no experience bending metal tubes, I'd say that the results were good, not perfect, but indeed good.
The trick is to bend each tube along the same plane and use the same bending technique. If you work as a team, I'd suggest that one person be dedicated to bending the tubes. That way, they'll all turn out pretty close to identical.
There are three schools of thought about fastening together a solar greenhouse such as this. The first is to use hose clamps so there are no holes drilled in the tubing. The second is to use commercial saddle clamps like the one shown lower right. The third approach is to fasten the tubing together using machine screws with nuts and self-tapping screws.
I elected to drill holes in the tubing and fasten it together using machine screws, nylon locking washers and sheet metal screws. Any hole in the metal tubing will weaken it a bit, but I don't see a 3/16 inch hole on either side of the tubing as being that much of a degradation of its material strength.
By using fasteners that penetrate the tubing, I have confidence that the structure is held together with friction and a type of dowel or pin that the machine screws constitute.
In any event, since the
solar greenhouse is your gardening structure, the choice is yours when it comes to design,
construction techniques and many other decisions. If you read about the
project details by following the link below, I think you'll be a bit
more tuned up in terms of my lessons learned.
Here are details about how I built solar greenhouse #3 for those of you who are interested in bending your own tubing to create a gardening structure like this.
I salute all my friends who plan for a life of greater self-reliance that includes growing their own produce. It's a great way to relax, and it's a healthy alternative to non-organic produce that makes up the lion's share of what's available in the commercial marketplace. I trust some of my ideas will encourage you to build your own solar greenhouse, or perhaps some other design, all with the intention of providing fresh produce for you and your family for years to come.