I grew up living next to my grandparents and spent many days working side by side, starting seeds and transplanting plants, with my grandfather in his greenhouse. It was a fairly good size with a stone foundation and glass panels. It was attached to his garage which had a furnace to heat the garage and greenhouse and had running water and electricity. I have many fond memories of spending afternoons with my grandfather in his greenhouse.
Now that I am older I often dreamt of having my own greenhouse so I could start seedlings in the spring, extend the season in the fall and possibly relive some of those childhood memories. For several years I looked into purchasing a kit but was discouraged by the high prices and cheap plastic panels they came with so I decided to do some research and design and build my own.
Three years ago, after spending countless hours deciding what size to build, what materials to use and what accessories to add, I finally built my greenhouse.
My original plan was to build the greenhouse out of cedar, but because this was my first attempt I didn't want to invest too much into something that might not be exactly what I wanted, so I decided to use pine 2 x 3's for the framing and 6 mil greenhouse plastic for the covering. The entire cost for the 6'-10" x 8' greenhouse the was less than $150.00 including all the hardware.
The greenhouse has two work benches, the one on the south wall is 24" high and the one on the north wall is 36" high. There is a vent/window on the wall opposite the door. The floor is covered with landscape fabric which seems to work well for now. The late spring sun can really raise the temperature inside, so I have added an automatic vent opener to the window this year. The vent opener can be adjusted to open and maintain a constant temperature inside. It has been working perfectly and has saved me on several occasions when I would have forgotten to open the vent in the afternoon or close it at night when the temps dip below 50 degrees.
This greenhouse has held up remarkably well considering the framing is untreated and unpainted pine. The greenhouse film is rated for 5 years and hasn't cracked, ripped or yellowed despite being exposed to the northeast bitterly cold and snowy winters.
This fall I am planning on building a new greenhouse. It will be a more permanent one so I am going to construct it out of 2 x 4 cedar. I am planning on making a larger one- probably 8' x 12'. It will have a crushed stone and paver floor, running water with irrigation system, more vents, shade screens and possibly a propane heater. I am also considering using polycarbonate panels instead of the 6 mil greenhouse film to try and better control heat loss in the winter.
I am working on putting together plans complete with assembly instructions and materials lists for both my greenhouse and the cold frames if anyone is interested in building one. I will post when they are available.
****** Update 9/29/12 - Greenhouse Plans are now available! ******