As part of our house remodel, we’ve replaced the windows, some of which were about the size of sliding glass door replacements – 76″ x 34″. One can also frequently find large panes of glass on craigslist. I looked around and could not find diy greenhouse plans to suit my design goals, so I built a 3 glass panel experiment (not shown). Some things I tried were problematic. The design described here addresses the problems uncovered in my experiment and I think this method is suitable for sharing with others. I will try to lay out step by step instructions to construct the greenhouse framework, and include a spreadsheet to compute the size of the structural pieces needed, based on the solar angle you want to use, the size of the glass pieces you are working with, and how deep (front to back) you want to make it.
These design constraints will not perfectly match those of all prospective builders. Here are some of the constraints that I considered:
- Being in the arid (U.S.) west, the meeting of the (wood) structure near the ground was not as great a consideration as if it had been in the eastern US with its moisture and humidity (and mold and rot)
- The north side of the structure is not considered useful in providing light. Many designs on the internet have glass on all four sides, but mine does not. The greenhouse is intended to be used November-April when we have cold nights. I have outdoor gardening space for the other part of the year.
- The design does not include ventilation or air movement to keep things cool (moderate) when the sun gets stronger. I eventually plan to design solar cooking capability into the glass panels for the summer months.
- The design has the front glass going close to the ground. The overhead clearance would also be low, but the design anticipates a dug walkway down the length of the greenhouse. That gives sufficient head room, and the excavated soil can be used to create the front seed bed.
The steps in implementing this design (they will have their own pages to elaborate):
- Download the design planning spreadsheet and plan based on the panes of glass you have available. Details.
- Construct the foundation of blocks. Details.
- Cutting the 2×6 frame for the glass pane. Details.
- Attaching the roof joists.
- Bracing the roof joists.
- Installing the frame for the back wall.
- Attaching structure to its neighbor.
- Adding glass supports and glass.
- Where to from here.