The next leap in urban design may very well be greenhouses. These are not the quaint and cluttered backyard hothouses with which you are familiar. Rather, these are veritable green compounds—more reminiscent of Star Trek than anything your eccentric neighbor owns. Take for example, the University of Arizona’s $450,000 greenhouse at the South Pole. Suddenly, the most extreme environment on earth can be depended upon to provide year-round produce. Gene Giacomelli, a contributing researcher on the project, declares unhesitatingly that greenhouses “can grow any crop anywhere at any time.”
Traditionally, the appeal of greenhouses has been their ability to support non-native plant species. However, recent scientific developments have endowed greenhouses with a new benefit—efficiency bordering on the absurd. According to Theodore Caplow, executive director of the engineering firm New York Sun Works, well-designed greenhouses use as little as 10% of the water and 5% of the area required by farm fields. The revolutionizing technologies are hydroponics and aeroponics, systems that cultivate plants in nutrient liquids and nutrient spray, respectively, rather than in soil.
Caplow’s firm is taking this advanced agriculture to the city. It has long been speculated that if greenhouses were erected on the all rooftops in New York City, they could supply double the amount of produce the city consumes annually. While converting every last urban rooftop may seem outlandish, Caplow maintains that there is an easy way to have a similar impact—farming the facades of office buildings. Double-glass facades are already a popular method employed by architects to save energy; the design allows winter sun in while insulating against heat loss. Conversely, in the summer, most double facades have built-in shades to keep the interior at room temperature. Caplow asserts that hydroponic gardens could be the source of that shade while simultaneously growing produce. In his design, plants cycle within the light-abundant space on vertical conveyor belts. Eventually, the matured plants transition to the lower floors for harvesting. Caplow assures, “The systems we are designing are what we can actually do today.”
Perhaps even more innovative is Columbia Professor Dickson Despommier’s design for a vertical farm. His blueprints reveal a full Manhattan block converted into a 30-story crop powerhouse. The skyscraper is designed to cultivate food through the use of grow lights and conveyor belts all powered by renewable energy sources. Approximately 100 kinds of fruits and vegetables would be grown on upper floors while the lower floors utilize the resulting plant waste to raise fish and poultry. Each floor would additionally employ sophisticated monitoring systems, including sensors for each plant that track its nutrient absorption, DNA chip technologies to detect the presence of plant pathogens, and a gas chromatograph to determine the maturity of the plant’s flavenoids. This may all seem wishful thinking, but like Caplow, Despommier maintains, “These are all right-off-the-shelf technologies. The ability to construct a vertical farm exists now.”
The promise of the vertical farm is profound. It is estimated that the year-round hydroponic production would yield 4 to 30 times that of farmland, depending upon the crop. There would be no weather-induced crop failure; no need for herbicides, pesticides, or fertilizers; and no infectious disease acquired at the agricultural interface. What’s more, vertical farms would revitalize the environment by eliminating agricultural runoff by recycling black water, adding energy back to the grid via methane generation from composting non-edible parts of plants, dramatically reduce fossil fuel use, and return current farmland to nature. Indeed, the Food and Agricultural Organization emphasizes that the best way to sequester carbon is to allow for the regrowth of cleared forest.
Admittedly, urban farms are not without some drawbacks. Caplow suggests that cultivating wheat, corn, rice, or orchard fruit indoors is not nearly as efficient as most fruits and vegetables. And of course there is the matter of price. Initially, at least, urban produce will likely be more expensive than that grown at farms.
But as time passes urban greenhouses are becoming a more viable solution. As Giacomelli aptly asserts, “All our cheap food is based on cheap transportation.” Furthermore, the strain of a swelling urban population—it’s estimated that by 2050 we’ll reach 9 billion, with 85 percent living in cities—may make vertical farming a godsend.
Despommier’s skyscraper farm has aroused global interest. Some of the most promising clients are governments lacking sufficient arable land. Indeed, Jordan, India, and China have already begun pursuing greenhouse economics. Ultimately, figures for the vertical farm suggest it could produce enough food for 50,000 people. The professor notes that with merely 160 of these buildings, “You could feed all of New York.”
Perhaps even more impressively, the Dutch-based PlantLab’s new Plant Production Units (PPUs) could supply one person with all their produce with ten square feet of space. To feed 100,000 people would only require the equivalent of two adjacent soccer fields stacked 10 levels high. Aside from the traditional agriculture requiring vastly more resources than vertical farming, it also has a significantly larger amount of waste. Indeed, PlantLab reports that more than 40% of food is wasted in the traditional supply chain from standard farms, collections and processing, distribution, wholesale, and market. PlantLab’s projected supply chain directly transports the food from the plant production unit to the market, significantly cutting down the time from harvest to table and the amount of food waste destined for the dumpster. Additionally, PlantLab’s design is entirely scalable. Their grow houses could be placed in any locality with PPUs ranging in size from microwaves to skyscrapers.
Ultimately, as the global population grapples with the scarcity of resources like potable water and arable land, major concerns around food security are increasingly prevalent. These innovative agricultural systems can do more than ensure the growth of off-season plants and more effective water and land use. They could be the answer to ensuring the global population has access to healthy, locally-sourced food.