I have a small garden in my backyard and I'm involved in a neighborhood gardening club (greenfield garden club, GGC).
Last month we had a guest looking to expand his worm composting farm from rural Ohio to Pittsburgh. His vision was to have lots of compost collecting bikes, some warehouses where the worms lived, and pedal powered harvesting mechanisms. It sounded pretty neat. His name is Matt Peters. It seems like he has a lot of experience in eco/green/alternative energy/composting, but lacks space in the city and money. Could be a good connection for your client, depending on where he is.
We (the GGC) are meeting on the evening of the 28th to tour the Hazelwood Gardens ( http://hazelwoodharvest.org/ ) which sounds like the urban farming thing you are looking for. They use abandoned property and kids from the community to grow food for people who need it. You should invite your client to tag along. Let me know if you want the details.
