Urban food production is an area which has been too frequently overlooked by development planners, considering global urbanization and the surprisingly large amount of food already produced in cities. Beyond the sites traditionally used by urban gardeners, there is considerable potential to involve millions of urban families, who may not at first thought seem to have a location to garden. This untapped potential is found where there is plenty of sunshine but either no soil or the soil does not lend itself to cultivation. ECHO and others have developed several "above-ground" techniques suited for such sites.
Where might sites for these above-ground gardens be found? For starters, in many cities there are countless hectares of sturdy, flat cement rooftops and many more hectares of tin roofs on insubstantial shanties. There are also steep hillsides, extremely poor soils, yards of rock or cement, spaces around tree roots, and places where land tenure is so unstable that only portable gardens are attractive.
Such areas were a natural challenge for us, since one of ECHO's purposes is to help people grow food under difficult conditions. There are few "soils" worse for gardening than a cement slab, a pile of rocks, a corrugated roof or a mass of tree roots. However, large areas of such unused but potentially prime growing space are often located in cities, near large markets and numbers of underemployed people. The potential value of creating growing areas in such locations is obvious.
Since 1982, ECHO has been working on methods for gardening in such situations, which are not nearly as difficult a challenge for gardening as one might think. In fact, cement slabs have become one of our favorite gardening spots in Florida, where sandy soils and nematodes make in-ground gardening a challenge. Urban gardening has a reputation of not being very successful. This chapter takes a second look at growing food in the city.