COMMENTARY: Urban farming is an urban myth
Then there is the question, ‘where are all those urban dwellers with the skills and the inclination to seriously grow food?’ I maintain there has been plenty of hype and encouragement in recent years for city folk to get out and grow food. It would be surprising if there is a latent population of closet gardeners who might spontaneously become active and tear up their lawns and make a go with veggies or fruit trees. It is doubtful if even this one percent of potential urban land resource could ever be utilized, given the lack of enthusiastic and capable gardeners. However, it should be noted that in developing countries food security issues, land use patterns, the presence of recent migrants with farming skills and household labor ability are quite different than in North America and, in such an environment, significant quantities of food are produced in urban settings.
What about the sustainability of urban farming in North America? At any garden center there are mountains of topsoil available in convenient plastic bags and by the truckload. That soil does not just “happen;” it was once farmland that has forever been removed from productivity in its natural setting. For example, as my urban home is located on a stony ridge, the original owners of the house brought in black soil by the truckload so they could have a lawn and plant some foliage and flowers. This is a classic case of urban land that was unsuitable for agriculture being made somewhat arable at the expense of productive farmland. Does anyone worry about “soil miles?”
Another often overlooked factor with urban farming is the water requirement. The water we get delivered to our homes by pipelines is potable and from a sophisticated and costly treatment system that is has little excess capacity for irrigation. For good reason, watering of lawns is frequently banned or restricted during dry periods. Furthermore, the gardener with the saddlebags (where did his soil come from?) and indeed all plants growing in containers face accelerated evaporation and require a lot more water to thrive than those plants growing in conventional soil.
Rooftop gardens for food production are also water guzzlers, given that the thin layer of soil on a cement surface requires much more than naturally provided by rain. This is because such a base for plants leads to higher soil temperature levels, accelerated evaporation and an inability to develop subsurface moisture reserves. Yes, household grey wastewater is a potential resource, but how many homes are realistically capable of capturing the water from showers, washing machines and the kitchen sink? In Toronto, to enhance city beautification, to reduce air conditioning energy requirements and to control waste water run off, all new commercial, industrial and public buildings with a flat roof of over 2,000 square feet must be developed (city bylaw) into some sort of garden. Because of the water issue, food production is out of the question and sedums, with their drought-tolerant waxy leaves, are the plant of choice. The cost of such gardens run at $270 a square foot or over $11 million per acre, which is about 3,000 times more expensive than some of the very best prime farmland. Not much promise here to feed the world.
As hobbies go, gardening arguably tops the list of activities that provide exercise, exposure to nature and a sense of pride in producing fresh nutritious food. Furthermore, as all human indulgences have some impact on the environment, the guilty pleasure of using some topsoil or water from the hose to grow a bit of food is perfectly acceptable. However, the bottom line is that urban farming is a myth when it comes to being a significant contributor to the nation’s food supply.
Gardeners everywhere - just get out there and enjoy yourselves and the bounty of your efforts. The burden of feeding the world, or even your community, should not be your concern.