I read this article on urban farming this weekend, and thought "heartwarming, but uselss." So far it's required subsidies of $1 million to produce a small amount of food--the Times glowingly says that it "provide(s) healthful food to 10,000 urbanites", but of course, all that means is that 10,000 people, give or take, have received at least one vegetable apiece. It's not providing anything like the majority of their food intake. And that's in a rust-belt city with a lot of spare land and spare labor.
Ezra argues that industrial agriculture gets subsidies too, and this is true--but not the things these people eat. More to the point, the subsidies are not why American agriculture has so many vile practices. What enthusiasm for these sorts of projects fail to deal with is scale.
Scale matters in two ways. First of all, scale is why so many promising pilot projects fail to yield results when they're implemented broadly--think how many terrific new education and medical programs you've read about over the years, which delivered mediocre results when they became more popular. Pilot projects have a deep pool of enthusiastic and skilled labor. There is the excitement of the new, of possible discovery, driving everything forward. Broad programs are applied by ordinary busy people with no stake in revolution. Over time, the enthusiasm wanes. Urban gardening is not new, after all--it was in vogue during the Settlement House movment, the 1940s, and again in the hippie sunset of my childhood, when I, along with the other children of PS 166, dutifully weeded little herb patches on 89th and Amsterdam. By the early 1990s, many of those lots had been abandoned or turned into condos.
Milwaukee, unlike many cities, probably has a lot of abandoned property. But it probably doesn't have an unlimited supply of urban farming volunteers, or people interested in buying organic local watercresss at $16 a pound. And if Milwaukee did try to grow most of its own food, it would have the problems that areas with lots of farms experience, like massive pest infestations. (Agriculture has terrific network effects--for bugs and mold spores). And, um, smells, which are the first thing that urban transplants to farm country tend to complain about, particularly if animals are involved. Don't grow animals, you'll say; they're bad for the planet anyway. But animals are key suppliers of key organic inputs like bone meal and manure.
Then there's the reason industrial agriculture is like it is: economies of scale. Agriculture has extremely high capital requirements, and thank God, because all that capital is the reason that you and I (aka Shiva, Destroyer of Houseplants) are spending our days on the internets rather than poking at weeds or staring at the back end of a mule. But capital means high fixed costs for land and equipment. Industries with high fixed costs naturally gravitate towards large producers who do a lot of volume. America has a lot of cheap land far from its cities, which is where that scale can be most easily achieved. The subsidies are pernicious, but they are a sideshow. Remove them, and it's quite possible that we'd see a more concentrated, more socially irresponsible industry forcing even more negative externalities onto the rest of us.
That scale has, up until now, been least achievable with produce. Produce is also the area of farming which recieves the fewest subsidies, probably because when our farming policy was framed, produce was a perishable sideline for most cash croppers. But as picking becomes more mechanised, and various technologies enhance the returns for those with capital to invest, that is changing. I don't see how urban or suburban farming becomes anything but a sideshow for a few committed souls. The returns to scale are simply too great.