Vertical farming – The Highs and Lows of Urban Agriculture

Vertical farming, an innovative concept, was first introduced in 1999 by Dr. Dickson Despommier, a professor of environmental health sciences at Columbia University. Faced with the growing challenges of feeding an urbanized world population, Despommier initially proposed rooftop gardens. However, after realizing that a New York City rooftop could only feed approximately 1,000 people, he began to think bigger and suggested a radical solution: growing plants on multiple layers stacked vertically. His vision centered on maximizing space efficiency in cities where land was limited.

Despommier and his students designed a futuristic 30-story vertical farm equipped with artificial lighting, advanced hydroponics, and aeroponics. The concept included the ability to grow around 100 kinds of fruits and vegetables on the upper floors, while the lower floors would house chickens and fish that could subsist on plant waste. This design could, in theory, feed up to 50,000 people in a self-sustaining urban farm.

While no such skyscraper farm has been constructed yet, Despommier’s idea ignited a wave of innovation, inspiring numerous smaller-scale vertical farms. Developers from major metropolises worldwide (from South Korea to Dubai, NYC, LA, Seattle, Toronto, Paris, Beijing, and Shanghai) expressed interest in the technology.

The first pilot vertical farm began operation in the UK in 2009 at Paignton Zoo Environmental Park, which used the farm’s produce to feed its animals. The garden served as an excellent educational resource to advocate for change in unsustainable land-use practices.

Building-Based Farms, Deep Farms, and Containers

In 2012, a new idea emerged in Chicago, Illinois: a company named The Plant housed its vertical garden system in an abandoned meatpacking building, opening the gate to sustainable farming within dynamically growing metropolises.

The world’s first commercial vertical farm opened in Singapore in 2012. The company, called Sky Greens Farms, featured over 100 small, 9-meter-tall towers.

Europe accepted the challenge in 2013 with the founding of the Association for Vertical Farming (AVF) in Munich, Germany. The organization unites growers and inventors with a common goal of improving food security, promoting sustainable development, and spreading advanced vertical farming technologies. In just two years, the AVF expanded throughout Europe, Asia, the USA, Canada, and the United Kingdom.

London entered the scene in 2015 when a company called Growing Underground began growing leafy greens in abandoned World War II tunnels. One year later, the Local Roots startup further innovated with the “TerraFarm” project, a vertical farming system hosted in shipping containers. TerraFarm was a completely closed-loop system equipped with advanced technologies, such as computer vision and artificial neural networks, to monitor the plants. The entire project was based in London but was monitored and directed remotely from California.

The results were remarkable: the TerraFarm units (40-foot shipping containers) produced the equivalent of “three to five acres of farmland” while using 97% less water. According to TerraFarm announcements, the project “has achieved cost parity with traditional outdoor farming,” thanks to the innovative idea of recapturing evaporated water through air conditioning.

In 2017, a Japanese company, Mirai, announced that its special LED lights could reduce growing times (lettuce grows 2.5 times faster). Using this technology, the company can produce 10,000 heads of lettuce a day in vertical gardens —100 times more than traditional methods would allow.

These contemporary vertical farms utilize advanced technologies such as LED lighting, fully automated climate control systems, and mostly hydroponic or aeroponic growing techniques. In doing so, they aim to optimize growth rates, maximize yield, and minimize water and pesticide use.

Technologies and Methods

Hydroponics

Hydroponics is a soil-less plant growing method that uses nutrient-rich water to sustain crops. Although researched since the 1930s, it became scalable at the beginning of the 21st century, requiring real-time sensory perception to control growth and the amount of water and nutrients. Advances in climate control systems and sensor technologies now allow farmers to monitor humidity, temperature, and CO2 levels, ensuring optimal growing conditions.

Aquaponics

The term aquaponics combines aquaculture (fish farming) and hydroponics. This method integrates plant production with aquatic organisms in a closed-loop system, mimicking nature. The nutrient-rich wastewater from fish tanks is filtered, and toxic ammonia is converted to nitrate using biofilters. The plants purify the wastewater, which is recycled back to the fish tanks. Additionally, the plants consume carbon dioxide produced by the fish, while the fish tanks provide heat to help maintain greenhouse temperatures.

Aeroponics

Aeroponics involves suspending plants and spraying their roots with a mist of nutrients. Developed by NASA in the 1990s for efficient plant growth in space, this technology uses no water or soil. Aeroponics is nearly waterless, using only 10% of the water compared to the economical hydroponic system.

Equipment and technical background

Artificial Lighting

In vertical gardens, energy-efficient LED lighting can simulate sunlight indoors, optimizing plant growth in environments that lack natural light. Special wavelength growth-enhancing lights can even accelerate plant growth compared to natural conditions. Additionally, this technology creates viable environments underground or in areas of limited sunlight, such as regions close to the poles.

Sensors and AI

In vertical gardens, real-time monitoring of the environment and growth is essential. Machine vision, air-analyzing sensors, and nutrient detection are crucial. Data collected by AI systems can help analyze and implement necessary changes immediately, optimizing growth cycles, monitoring plant health, and managing resources.

Altogether, vertical farms have ushered in the era of controlled-environment agriculture (CEA), which modifies the natural environment to increase yield or extend the growing season. Originally, CEA systems were hosted in greenhouses or buildings where environmental factors could be controlled. Vertical farming extends the utilization of these integrated systems.

With sensors and AI, vertical farms can be more effective and economical than traditional farming. Additionally, by incorporating automation and robotics for seeding, harvesting, and maintaining plant health, labor costs and human error can be significantly reduced.

Energy Usage in Vertical Farming

While vertical farming is resource-efficient in many respects, it consumes significant energy, particularly for artificial lighting and climate control. To mitigate expenses, many vertical farms are increasingly powered by renewable energy sources like solar panels or are located near energy-efficient urban centers to offset their carbon footprint.

Agricultural and Economic Aspects – The Future

Vertical farming presents a revolutionary solution for growing food in areas where arable land is scarce or where climate conditions are harsh. The ability to grow crops year-round, unaffected by weather, offers significant potential for urban areas and regions facing food security challenges.

Traditional farming’s arable land requirements are too large and invasive to remain sustainable for future generations. With rapid population growth, it is expected that arable land per person will drop by about 66% by 2050 compared to 1970. All-season vertical farming can multiply productivity by a factor of four to six, depending on the crop; for crops such as strawberries, this factor may be as high as 30.

Vertical farming also allows for a greater variety of harvestable crops due to its isolated crop sectors. Unlike traditional farms, which harvest one type of crop per season, vertical farms can grow and harvest multiple crops simultaneously.

A metropolis-based vertical farm produces food that travels a short distance to stores, in contrast to traditional farming methods. The United States Department of Agriculture predicts that the worldwide population will exceed 9 billion by 2050, with most people living in urban areas. Vertical farming is seen as a potential solution to the looming food shortage as the population grows. This environmentally responsible method lowers emissions and reduces water needs. Urban farming enables nearly immediate farm-to-store transport, cutting distribution costs and minimizing the carbon footprint of agriculture.

Economically, vertical farming is capital-intensive, requiring significant upfront investment for infrastructure, technology, and energy. However, the long-term benefits—including reduced transportation costs, water usage, and reliance on pesticides—can outweigh these costs. As technology scales and becomes more affordable, vertical farming could emerge as a key player in sustainable agriculture, particularly in densely populated areas.

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