Thank you, Thomas.
The reason I stated that a stand of trees, affording almost full shade during the heat of the day, would allow a greenhouse to remain cool, or at least at/near the ambient temperature, is because that's what I see with one of mine. A canopy or awning, mimicking the tree-shading, should do the same thing. I would think that it would have to completely shield the entire greenhouse from the sun for it to be efficient.
Whatever you end up doing, please keep us informed. Almost everyone faces the problem with super-heated greenhouses, particularly those of us who have the sun high in the sky during the spring and summer. Perhaps those in the northern tier of states and Canada don't have quite the problems with heat that we do down here.
