I loved seeing this video clip because I’ve heard a lot about these urban ag entrepreneurs who are using hydroponics to grow food in a clean, efficient, and environmental way. The load, or weight, of a soil based garden on a roof is immense making it out of the question for many buildings. Hydroponics offers an solution. However, return on investment for a set up like Chef John Mooney has in this clip has got to be incredibly long-term. I suppose it all depends on how much he is charging for a salad. If a small dinner salad costs $20 the ROI might be pretty good. However, I don’t see this technology taking off en mass until the start-up costs come down. I think one of those “trees” costs about $500, or so I read in a Q & A with Chef Mooney. The average building owner is not going to invest thousands and thousands of dollars into a computerized hydroponic garden that needs to be maintained and monitored. I guess that is where these roof top farmer entrepreneurs come in!