The asphalt garden: advances in permaculture

A future scenario. 

Excerpts from the article by Andrea Ward, may 2010, for the Continuing Education Center, of Mc Graw Hill editions:

Urban farms are cropping up in cities across the nation, bringing hyper-local food options and greener streetscapes to areas that once lacked both.

When we think of fresh vegetables in the city, we often think of the farmers market. Now a staple of many an urban neighborhood, farmers markets provide a space for connecting the urban with the rural, bringing together the growers of our food with those who eat it in a celebration of one of the planet’s most elemental transactions. But while the shoppers at farmers markets tend to be intensely local, many walking from nearby residential areas, most of the vendors truck their wares in from outlying rural areas—an average of 56 miles for a piece of produce sold as “local,” according to the Leopold Center for Sustainable Agriculture. That’s a far cry from the 1,500 miles that the average American supermarket vegetable travels before it’s eaten. But with nearly 80 percent of Americans now living in urban areas and food transportation energy accounting for as much as two-thirds of the energy required to grow it, there’s a powerful argument to be made for keeping the foods we grow, buy, and eat even closer to home—in the backyards, vacant lots, and rooftops of even our most densely built urban areas.

Community gardens, still growing in popularity, are increasingly seen as a valued use of land by municipalities and a worthwhile pursuit for residents interested in greening their neighborhoods and gaining food self-sufficiency. This is especially true in neighborhoods that have been hit hard by unemployment and economic disinvestment. Detroit is a case in point: the city’s unemployed and underemployed number near 50 percent, and approximately 30 percent of lots in the city are vacant. Community gardens are filling the void in neighborhoods and providing sustenance for residents struggling to get by.

Research shows that there is far more open land in American cities than one might think. A study by the Brookings Institution in 2000 looked at 70 major U.S. cities and found that an average of 15 percent of the land area within them was vacant. 

Places like Providence’s City Farm show that, given the right approach, it’s possible to make market gardens and commercial urban farming operations viable with less space than you might think. Pederson, who was hired at City Farm eight years ago, introduced a variation on the “biointensive” method of farming that allows City Farm to sell vegetables to local restaurants and at three different local farmers markets, while still having leftovers to give to farm volunteers and neighbors—with just 5,000 square feet of their 3/4-acre lot dedicated to vegetable cultivation. Developed in the 1960s, biointensive methods focus on building soil while producing large yields from a relatively small land area. At City Farm this means double-digging the top two feet of soil to alleviate compaction and increase drainage, building permanent rounded beds with walkways to accommodate workers, and planting with particular spacing (depending on the plant), using a hexagonal rather than the more conventional row-based layout. 

Biointensive farming on the asphalt  

Rooftop agriculture

Permaculture—a hybrid of the words “permanent” and “agriculture”—is another alternative agriculture method that has the potential to transform urban neighborhoods through the design of landscapes that integrate agricultural and human communities using systems that mirror natural processes. By definition, permaculture landscapes are often anchored by perennial crops, including fruit trees, and sustained by natural systems like onsite composting. A project called Pittsburgh Food Forests, begun in 2009 in a blighted section of Pittsburgh’s Hazelwood neighborhood, aims to establish permaculture landscapes throughout the city—“forests” with perennial fruit and nut crops and vertical layers of food production, including annual and perennial understory species, vines, and root crops growing near and underneath the food-producing trees. According to Juliette Jones, co-manager of the project, the goal is to train and involve members of the surrounding community in stewardship of the forests and share with them the fruits of the harvest—and ideally inspire people to create similar landscapes near their own homes.

Rooftops are also increasingly being seen as a “land” resource with farming potential. Green-roof systems, like those installed on many high-performance buildings to minimize the heat-island effect and mitigate stormwater runoff, are not commonly used to cultivate vegetable crops—mostly sedums or similar cover species. But container vegetable gardening on rooftops has a long history in urban areas, and many rooftop farmers are branching out into ever more extensive systems.

Hypothetical scenarios of a future in which all food production will necessarily be local have prompted some to envision vast urban landscapes stacked with vertical acres of skyscraper farms—controlled, heavy-infrastructure (and capital-intensive) environments growing food crops indoors under conditions bearing little resemblance to anything that fits the current definition of a farm. But those solutions are far from being realized, and the optimism that exudes from urban farmers working in the current, more down-to-earth models suggests that the need for them may not arise. One statistic that many city farmers know and cite when asked whether cities have the capacity to feed themselves: During World War II, 40 percent of all the vegetables consumed in the United States were grown by citizen farmers in 20 million backyard “victory gardens.”

http://continuingeducation.construction.com/article.php?L=5&C=679&P=1

All images from Image from Continuing Education Center