Hopefully you will be able to use it for hydro soon, especially after all that work and money. I haven't decided weather I will buy a greenhouse or build it from scratch. I need to do some pricing of materials first, as well as map out exactly where it will go, and how big it will be. Maybe it will cost less to build 2 or 3 smaller ones instead of one larger one.
If I bought one I will need to modify it, and I will need to take the cost of that into consideration. If I didn't modify it, I would never be able to grow anything in it during summer. The outside air temp can reach 128 degrees during the summer months. Inside a greenhouse that is sitting in the sun, the air temp would out of control. It would cost way to much to run air conditioners in it to get it down to a reasonable temp. If wasn't see through, I would need to run
lights in it, wasting all that free sunlight.
What I have in mind is building it so that it is see through like a regular greenhouse, but adding removable lightproof panels to the outside (white to reflect light and not absorb heat). These panels would only be needed half the year during the summer months when it's hot. But now I need to bring the light inside. I plan to use a series of Tubular Skylights to do this. I may even make my own, they don't need to be pretty.
Tubular Skylights, all of the benefits, none of the problems
Natural Sky Lighting
Tubular Skylights
These will bring in the light without the heat. I think the best way to do this is to build the greenhouse with the see through panels, but making them removable. Then I wouldn't need to cut through them to install the Tubular Skylights, I would simply swap out the see through panels with the light proof ones. This should make the cost of adding AC to the greenhouse much more reasonable, and still allow me to grow in natural light.