h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The November 2010 issue of Atlantic Magazine had an interview with John Hantz.
this entrepreneur wants to invest $30 million in a plan to reinvent Detroit.
He envisions the worlds largest urban-farm.
Here is part of what he said:

We have gone from two million people to 800,000.
There are over 200,000 abandoned parcels of land -and by debatable estimates-30,000 acres of abandoned property.
HE ENVISIONS A PROJECT THAT
will deal with aeroponics and hydroponics and breakthrough ideas in urban-ag industry. The world is going to change, and Detroit could be ground zero for new engineering and manufactruring of indoor growing systems.
It might be noted that Michigan now allows caregivers to grow small amounts of medical marijuana if they do it indoors in a secure area.
One might suspect this man of planning for future changes in the law that would allow this crop to be grown commercially.