You definitely do not want to integrate a solar furnace into your envisioned rooftop, green environment. The climate you described seems better suited to a pergola or some other form of overhead shading structure.

I would explore design variations based upon traditional and vernacular methods of shading plants in urban and agricultural areas of your country. Start with vertical uprights selected in appropriate materials and order, adhering to whatever architectural style your design sensibilities dictate. They should be spaced according to the appropriate spans, proportion and scale. The selection of horizontal members, needs to be carefully considered as well.

With that said, choices of shading materials can only be recommended after a careful analysis of all the above. Fabrics are a popular choice, but tend to collect dust and debris if applied over an open structure. Perhaps an alternating layer of rot resistant wood slats, secured over pergola stringers could work - canted against the prevailing sun's position.

Wind blocks, consisting of alternating wooden components -not unlike lattice panels - could be applied to the vertical columns/posts and overhead beams - again, repeating the stylistic theme. The various choices are endless - restrained only by local building code regulations, your budget, and your imagination.

Hi
What you want is a "Shadehouse" not a GH. I'm guessing you never have freezes?? How about rainfall??
It is a heck of a lot easier to heat rather than cool not to mention cheaper . Even a SH might not be necessary
in you area especially for veggies . Wind protection is obvious but don't completely block the air for sure.
You can google sh's for ideas but even better would be local advice . Can you see any examples ,talk to people who are doing this?? They will steer you clear of a lot of mistakes and save you a bundle. gary

Thank you both for your answers (I'm sorry for the delay in responding -- I thought I'd receive notices when answers were posted).

Gary, I'd kind of arrived at the same conclusion -- I need perhaps some shade if the sun is too intense, but I'm getting the impression that with adequate watering and decent protection from the wind my veggies should be ok.

I've decided to place the plants on one side of a storage area, such that they're protected from the brunt of the wind by the building. There's still some wind that gets around the edges, and I need to see how bad it is up there when it gets gusty, but I think I'll be ok.

If necessary I'll build a simple shade structure out of wood and attached to the side of the building, which I would cover with shade fabric. I think I'll only do this though if I see any trouble from the sun with my plants.

I've bought two Earthboxes to start with, and will be planting tomatoes (in the Earthboxes), basil, rosemary and zucchini (in other containers) to start with. As I've seen suggested elsewhere, my goal this season is more to make sure something survives; I'll set loftier goals for next year if things turn out ok. :)

I hope that it's not too late in the season to be starting this, but I'm counting on the fact that our winters are very mild and short, so I hope to be getting about two harvests between now and year end.

And, as an aside, I'm not aware of anyone else doing this kind of rooftop gardening here in Monterrey (aside from purely ornamental gardening if they have a rooftop deck), in spite of the fact that our architecture typically has flat roofs and small-to-nonexistent yards, which would seem to be ideal for the purpose.

I hope that if it works out well, I can be a sort of evangelist for the idea. Rooftop gardening, aside from its uses for food production, would be a tremendous boon to helping ameliorate the terrible heat island we've created in this city between the asphalt and the hot roofs.

hi
I live in s. florida so have a distinct summer winter season so I mainly grow veggies during winter.
Most veggies need lots of sun but resent temps above 90 and especially warm nights.
If you never have frosts and not too high a humidity you could probably grow year around. Of course there are tons of "tropical" veggies that love the heat lol
I mostly use my shadehouse for orchids and understory palms. Though i have those pesky few days or hours of frost ,heat is runaway the main problem. lol good luck with whatever you decide. gary

I think it would be interesting to build some sort of a gazebo with plastic that could be attached when it is cold, batting (like is used in quilts) for when less intense sun or slightly cooler temps and less winds are desired, or just left open when nice weather is to be had. Maybe hinged benches could be built in that could store the plastic and batting. On especially cold nights or if some plants were trellised against the "walls" of the gazebo you could hange batting next to the plants and then the plastic so that when the sun comes up if it gets suddenly hot that the batting would separate the plastic from the leaves of the plants but yet they would have the protection of the plastic?????? Just a thought I am toying with as I am a recent transplant to the high desert but I dont know much about GHs and I'm not an engineer or anything..... just a mom who likes to garden.