I'm trying to picture it and don't quite understand the 4' x 4' window for the long side. Aren't the sides made out of the wavy plastic stuff too? You don't really need a window on one side or a screen for summer. The vents on the top of the short sides will be the best ventilation since the heat will rise. you could put a fan on one end to pull the heat out and that will pull fresh air in through the other end.

If you open a large window in summer you will lose your humidity inside and that's one of the things you want to keep in the greenhouse if you are starting seedlings. I have found that seedlings didn't start so well in my greenhouse without heat mats under the flats and supplimental lighting real close to the tops of the flats. The seedlings also like a fan after they have germinated to keep them dry and make them strong, so you should try to plan for electricity in your greenhouse.

Other than that, I think your greenhouse lean-to is a great idea.

Since we're planning a custom greenhouse in the near future, which I plan on designing/building myself, I'm researching all viable options for dimensions, forms, materials and aesthetics. It will be free-standing, have top ventilation, with dimesions TBD.

The notion of using corrugated plastic was never a consideration - but upon reading this post, I decided to keep an open-mind in spite of my desire to use only "green" conventions.

However, after an image search of greenhouse sheds - using the "wavy stuff", I've become less enamoured with the idea of using this material. Case-in-point as follows:

It does look sort-of-cool, has its merits and most likely is very economical to build . . . but in reality, and JIMHO, I've never really warmed up to these plastic fantastic fabrications.

I'll try this again with the pic attached . . .

{{gwi:299089}}