Already, we have large-scale indoor farms such as EuroFresh Farms in Willcox, Arizona (318 acres (1.3 square km) of one-storey-high hydroponic greenhouses), supplying fresh tomatoes and cucumbers, and FarmedHere in Bedford Park, Illinois, a 90,000 square-foot (8,360 square metre) empty warehouse several storeys tall that was converted into an indoor farm producing tilapia (freshwater fish), a variety of leafy green vegetables, and several value-added products. Indoor farms (controlled environment agriculture or CEA) will undoubtedly replace most outdoor urban agricultural initiatives as the advantages of farming within protected environments become more widely accepted.
Judging by current trends in the development of advanced technologies, city-based CEA appears to have a bright future, as newer strategies emerge enabling indoor farming to be carried with increasing efficiency. Grow lights, for instance, have evolved from ordinary fluorescent light fixtures – expensive to operate – into a series of light-emitting diode (LED) lighting schemes. These LED lights can be adapted to emit light spectra at two dominant wavelengths (red 680nm; blue 460nm) tailored for growing green plants. The benefits of LED grow lights are obvious when compared to other outdated lighting schemes: LEDs cost less to run, and produce greater yields of most commercial crops, such as leafy greens and tomatoes. In early 2013, Phillips in the Netherlands announced it had invented an LED light with energy efficiency 150% greater than existing LED grow lights. This new development promises to significantly reduce energy costs involved in growing such crops.
Although most current vertical farming operations have chosen to specialise in cash crops consisting of leafy green vegetables (easy to grow and much in demand), in the near future, consumers are likely to ask for a wider variety of vegetables and fruits grown without pesticides, herbicides and other harmful chemical contaminants. At that point, vertical farming in tall buildings will replace less productive single-story greenhouses as the source of all city-grown produce. Some form of vertical farming now exists in Japan, Korea, Singapore, the United States, and Canada. New vertical farms are planned for a number of cities in the United States (Milwaukee, Memphis and Jackson Hole in Wyoming), and Linköping, Sweden.
Urban agriculture has the potential to become so pervasive within our cities that by the year 2050 they may be able to provide its citizens with up to 50% of the food they consume. In doing so, ecosystems that were fragmented in favour of farmland could be allowed to regain most of their ecological functions, creating a much healthier planet for all creatures great and small.