I have been woolgathering lately about the possibility of setting up a system of garden plots in the city to create a "farm".
The city is filled with unused space. You can find it anywhere. The key is how you would be able to manage a system of distributed small plots. We have a tendency of thinking about farmers as lantern-jawed white guys sitting in their combines and bringing in the wheat harvest. That isn't gonna go away, but it sure is gonna change.
Most of the fruits and vegetable that we enjoy here in the city were probably grown down in a mega-farm in the imperial valley, loaded on a truck, and shipped to where we live. I can't say that I see this as a viable long term solution.
But I do see a solution where a person might be able to "sharecrop" a bunch of garden plots in his area to produce vegetables. A percentage of the yield would go to the landowner as payment, the rest would go to the sharecropper as his cut. A booth in the Saturday market or a route of paying customers and access to vegetables would be the sharecropper cut.
Now don't get me wrong, this would not be a way to "live the dream". It would be damn hard work. But it has the advantage of low capital outlay and access to foodstuffs outside of the current "iffy" system of agriculture and distribution.