[thinkcontext]

The water issue is independent of whether the farm is vertical or not. There are plenty of hydroponic farms that are in a traditional horizontal orientation, I presume aeroponics can be setup this way as well. So, I do think the smaller area is the main advantage, though I'm not convinced it is a compelling enough reason given the increased energy, land and capital costs.

I agree that water should be treated as more valuable and scarce than it currently is. You mentioned the Middle East, I saw this concept for a "seawater greenhouse" recently in Qatar and was intrigued

http://www.sciencemag.org/news/2013/11/desert-farming-experi...

In the US, I'm curious about the scalability of these water saving technologies. Could they replace a significant percentage of vegetable production of drought stricken California? As I understand it now, hydroponics is used primarily for winter production, even that competes with Colorado River dependent Arizona.

[simopaa]

You are absolutely correct about that the water aspect is not vertical related in any way. I'm just used to seeing vertical and aeroponics going so hand-in-hand that I totally forgot about the possibility to have horizontal aeroponic greenhouses.

I'm very curious as well about all of these water reducing efforts, since that may well be the largest thing that threatens the food supply in the coming decades.