What is Vertical Farming?
The term vertical farming was coined by Gilbert Ellis Bailey in 1915 in his book of the same name. He wrote about farming with a special interest in soil origin, its nutrient content, and the view of plant life as vertical life forms, specifically relating to their underground root structures.
His use of the term differs from the current meaning – modern usage of the term vertical farming usually refers the practice of producing food in vertically stacked layers, such as in a skyscraper, used warehouse, or shipping container. The modern ideas of vertical farming use indoor farming techniques and controlled-environment agriculture, or CEA technology, where all environmental factors can be controlled. These facilities utilize artificial control of light and environmental controls such as humidity, temperature, gases, and fertigation. Some vertical farms use techniques similar to greenhouses, where natural sunlight can be augmented with artificial lighting and metal reflectors.
Types of Vertical Farms
Mixed-Use Skyscrapers – Mixed-use skyscrapers were proposed and built by the architect Ken Yeang. Yeang proposed that instead of hermetically sealed mass-produced agriculture, plant life should be cultivated within open air, mixed-use skyscrapers for climate control and consumption. This version of vertical farming is based upon personal or community use rather than the wholesale production and distribution of plant life that aspires to feed an entire city. It thus requires less of an initial investment than Despommier’s vertical farm.
Despommier’s Skyscrapers – Plant life is mass-produced within hermetically sealed, artificial environments that have little to do with the outside world. In this sense, they could be built anywhere regardless of the context. Although climate control, lighting, and other costs of maintenance have been posited as potentially stifling to bringing this concept to fruition, advocates have countered that an important feature of future vertical farms will be the integration of renewable energy technology, be it solar panels, wind turbines, water capture systems, biomass, and probably some combination of the four. The vertical farm is designed to be sustainable, and to enable nearby inhabitants to work at the farm.
Stackable Shipping Containers – Several companies have brought forth the concept of stacking recycled shipping containers in urban settings. Freight Farms produces a leafy green machine that is a complete farm-to-table system outfitted with vertical hydroponics, LED lighting and intuitive climate controls built within a 12 meter by 2.4-meter shipping container. Podponics has built a large scale vertical farm in Atlanta consisting of over 100 stacked growpods. A similar farm is currently under construction in Oman.
Obstacles to Vertical Farming
Economics – Opponents question the potential profitability of vertical farming. At current levels of technology, the ability of vertical farms to compete with established farming processes is limited. The extra cost of lighting, heating, and powering the vertical farm may negate any of the cost benefits received by the decrease in transportation expenses. The initial building costs will be easily over $100 million, for a 60-hectare vertical farm. Office occupancy costs can be very high in major cities, with cities such as Tokyo, Moscow, Mumbai, Dubai, Milan, Zurich, and Sao Paulo ranging from $1,850 to $880 per square meter, respectively.
Energy Use – During the growing season, the sun shines on a vertical surface at an extreme angle so that much less light is available to crops than when they are planted on flat land. Therefore, supplemental light would be required in order to obtain economically viable yields. Bruce Bugbee, a crop physiologist at Utah State University, believes that the power demands of vertical farming will be too expensive and uncompetitive with traditional farms using only free natural light. As the Vertical Farm proposes a controlled environment, heating and cooling costs will be at least as costly as any other tower, but there also remains the issue of complicated, if not more expensive, plumbing and elevator systems to distribute food and water throughout. Even throughout the northern continental United States, while heating with relatively cheap fossil fuels, the heating cost can be over $200,000 per hectare.
Pollution – Depending on the method of electricity generation used, regular greenhouse produce can create more greenhouse gases than field produce, largely due to higher energy use per kilogram of produce. With vertical farms requiring much greater energy per kilogram of produce than regular greenhouses, mainly through increased lighting, the amount of pollution created will be much higher than from field produce. The amount of pollution produced is dependent on how the energy used in the process is generated. Greenhouse growers commonly exploit photoperiodism in plants to control whether the plants are in a vegetative or reproductive stage. As part of this control, growers will have the lights on past sunset and before sunrise or periodically throughout the night. Single storey greenhouses are already a nuisance to neighbors because of light pollution. A thirty storey vertical farm in a densely populated area will surely face similar problems because of its light pollution. Hydroponic greenhouses regularly change the water, meaning there is a large quantity of water containing fertilizers and pesticides that must be disposed of. While solutions are currently being worked on, the most common method of simply spreading the mixture over a sufficient area of neighboring farmland or wetlands would be more difficult for an urban vertical farm.
Potential Advantages of Vertical Farming
Preparation for the Future – It is estimated that by the year 2050, close to eighty percent of the world’s population will live in urban areas and the total population of the world will increase by three billion people. A very large amount of farmland may be required depending on the change in yield per hectare. Scientists are concerned that this large amount of required farmland will not be available and that severe damage to the earth will be caused by the added farmland. According to Despommier, vertical farms, if designed properly, may eliminate the need to create additional farmland and help to create a cleaner environment. He recommends that the structures have built-in renewable energy systems.
Increased Crop Production – Unlike traditional farming in non-tropical areas, indoor farming can produce crops year-round. All-season farming multiplies the productivity of the farmed surface by a factor of four to six times, depending on the crop. With some crops, such as strawberries, the factor may be as high as thirty times. Despommier suggests that, if dwarf versions of certain crops are used, e.g. dwarf wheat, which has been grown in space by NASA and is smaller in size but richer in nutrients, year-round crops, and stacker plant holders are accounted for, a thirty storey building with a base of a building block about two hectares, or five acres, would yield a yearly crop analogous to that of 1,000 hectares, 2,400 acres, of traditional farming.
Protection from Weather Related Problems – Crops grown in traditional outdoor farming suffer from the often suboptimal, and sometimes extreme, nature of geological and meteorological events such as undesirable temperatures or rainfall amounts, monsoons, hailstorms, tornadoes, flooding, wildfires, and severe droughts. Because vertical plant farming provides a controlled environment, the productivity of vertical farms would be mostly independent of weather and protected from extreme weather events. Although the controlled environment of vertical farming negates most of these factors, earthquakes and tornadoes still pose threats to the proposed infrastructure, although this again depends on the location of the vertical farms. Additionally, there will be a potential savings on insurance premiums as fewer issues jeopardize the produces’ growth.
Conservation of Resources – Each unit of area in a vertical farm could allow up to twenty units of area of outdoor farmland to return to its natural state, and recover farmlands due to development from original flat farmlands. Vertical farming would reduce the need for new farmland due to overpopulation, thus saving many natural resources currently threatened by deforestation or pollution. Deforestation and desertification caused by agricultural encroachment on natural biomes would be avoided. Also, because vertical farming enables crops to be grown closer to consumers, it would substantially reduce the amount of fossil fuels currently used to transport and refrigerate farm produce. Producing food indoors reduces or eliminates conventional plowing, planting, and harvesting by farm machinery, also powered by fossil fuels.
Halting Mass Extinction – Withdrawing human activity from large areas of the Earth’s land surface may be necessary to slow and eventually halt the current anthropogenic mass extinction of land animals. Traditional agriculture is highly disruptive to wild animal populations that live in and around farmland and some argue it becomes unethical when there is a viable alternative. One study showed that wood mouse populations dropped from twenty-five per hectare to five per hectare after harvest, estimating ten animals killed per hectare each year with conventional farming. In comparison, vertical farming would cause very little harm to wildlife, and would allow disused farmland to return to its pre-agricultural state.
Impact on Human Health – Traditional farming is a hazardous occupation with particular risks that often take their toll on the health of human laborers. Such risks include exposure to infectious diseases such as malaria and schistosomes, exposure to toxic chemicals commonly used as pesticides and fungicides, confrontations with dangerous wildlife such as venomous snakes, and the severe injuries that can occur when using large industrial farming equipment. Whereas, the traditional farming environment inevitably contains these risks – particularly in the farming practice known as slash and burn – vertical farming reduces most or all of these dangers, because the environment is strictly controlled and predictable. Currently, the American food system makes fast, unhealthy food cheaply while fresh produce is less available and more expensive, encouraging poor eating habits. These poor eating habits lead to health problems such as obesity, heart disease, and diabetes. The increased availability and subsequent lower cost of fresh produce would encourage healthier eating.
Reduce the Risk of Poverty – Food security is one of the primary factors leading to absolute poverty. Being able to construct farmland in secure areas, as needed, will help alleviate the pressures causing crises among neighbors fighting for resources, mainly water and space. It also allows continued growth of culturally significant food items without sacrificing sustainability or basic needs, which can be significant to the recovery of a society from poverty.
Urban Growth – Vertical farming, used in conjunction with other technologies and socioeconomic practices, could allow cities to expand while remaining largely self-sufficient food wise. This would allow for large urban centers that could grow without destroying considerably larger areas of forest to provide food for their people. Moreover, the industry of vertical farming will provide employment to these expanding urban centers. This may help displace the unemployment created by the dismantling of traditional farms, as more farm laborers move to cities in search of work.
Energy Sustainability – Vertical farms could exploit methane digesters to generate a small portion of its own electrical needs. Methane digesters could be built on site to transform the organic waste generated at the farm into biogas which is generally composed of sixty-five percent methane along with other gases. This biogas could then be burned to generate electricity for the greenhouse.