I was introduced to the concept of vertical farming this week. It’s the first time I had heard about this term and I pictured something like the Oasis of Aboukir (French: Oasis d’Aboukir) in Paris by Patrick Blanc. I was wrong: vertical farming doesn’t mean plants on the façade of a building.
Vertical farming is a way of making the existing horizontal form of agriculture land vertical. Facing population growth, limited arable land, problems with the water sources and pesticide used for agriculture, vertical farming poses a new solution to the problem of feeding us. On the macro level, it helps alleviate a shortage of food supply, agricultural land, and aging agricultural labor. On the micro level, vertical farms can be aesthetically pleasing and beneficial for occupants.
Here are three well-known examples of vertical farms:
Sunqiao, Shanghai, China
The most famous Sunqiao Urban Agricultural District in Shanghai is an example of vertical farming in the large-scale controlled greenhouses. It serves a purpose both for production and education.
Japan is known for its limited land and expensive labor. Additionally, people have been concerned about food nutrition and safety issues after the 3/11 earthquake.
Vertical farming in Japan is therefore largely supported by the federal and local governments. Mirai not only uses different techniques to create a better and controlled environment for plants in their large factories, but also integrates its small production system in retail stores, roadside stands, restaurants, and shopping malls.
The system responded quickly after the 3/11 earthquake: an indoor farm was built in Miyagi after the disaster. Similarly, a three square meter system was built in 2008 under the extreme weather in the South Pole Showa Station to supply fresh vegetables.
Vertical farms in Japan now highly versatile. A Japanese VF company called Spread is using robots to further increase efficiency and control.
AeroFarms, Newark, NJ, USA
AeroFarms in Newark is very close to New York. Obviously, it aims to feed the large population in the New York Metro area. AeroFarms produces 2 million pounds of food per year in its facility. AeroFarms uses a closed-loop aeroponics system to mist the roots with nutrients, water, and oxygen; Mirai in Japan uses hydroponics. Aeroponics systems use 95% less water than field farming, 40% less than hydroponics, and zero pesticides.
Challenges and opportunities: lighting
Up to 2014, the data collected by the Institute of Environment and Sustainable Development in Agriculture at the Chinese Academy of Agricultural Science indicate that 1/3 of the vertical farming in China use artificial light, and the remaining 2/3 use solar light, along with a hydroponic system in the controlled environment greenhouses.
Daylight harvesting in the buildings are great for human wellbeing, but also provides free resources for the plants. However, in some regions where the solar radiation isn’t sufficient, an artificial LED light which mimics daylight is a choice. The cost of the operating lights 7×24 is substantial.
I would think the innovative way to introduce sunlight to a farm during the daytime is to save a portion of the power. The Lowline Lab in New York, the world’s first underground park, is a great experiment: it uses optical devices, protective tubes, and a solar canopy to bring solar light to the plants underground.
Vertical farming requires ventilation systems to bring the outside cool air for the plantation. The initial cost of the system and long-term maintenance costs for the ventilation system are high. Vegetables from the vertical farm are usually more expensive than those from regular fields and greenhouses.
An air exchanger can be used for introducing the outside cold air to the farm; there are some commercial high performance air exchangers available. Some advanced enthalpy recovery ventilators can recover moisture as well.
Most vertical farms use hydroponics, while very few use aeroponics. Aeroponics is, after all, relatively new. But thinking about the 95% of water savings using aeroponics, it’s clear that we need to do more research on aeroponics to make it more industrial and scalable.
Vertical farming can also be inside a building. Mirai sets many good examples as to how the farm can be so small as to fit into any building. The “We are the world” (天下一家) pavilion for the Shanghai World Expo 2010 demonstrated a conceptual indoor farm in the kitchen, something which is completely possible in any buildings.
Vertical farming is still at its early stages, which means a great potential for innovations to meet the challenges. Only if vertical farming can become profitable on a large scale, will it eventually solve the problems of urban food scarcity and local production.