Vertical Farming: changing face of farming

Prime agricultural land can be scarce and expensive. With worldwide population growth, the demand for both more food and more land to grow food is ever increasing. But some entrepreneurs and farmers are beginning to look up, not out, for space to grow more food.

One solution to our need for more space might be found in the abandoned warehouses in our cities, new buildings built on environmentally damaged lands, and even in used shipping containers from ocean transports. This solution, called vertical farming, involves growing crops in controlled indoor environments, with precise light, nutrients, and temperatures. In vertical farming, growing plants are stacked in layers that may reach several stories tall.

Although small, residential vertical gardening (including window farms) has been around for decades, commercial-scale vertical farms can change the face of farming in new way in India. But the interest in this new farming technology is growing rapidly, and entrepreneurs in several Indian cities are taking a serious look at this innovative farming system.

Types of Vertical Farms

Vertical farms come in different shapes and sizes, from simple two-level or wall-mounted systems to large warehouses several stories tall. But all vertical farms use one of three soil-free systems for providing nutrients to plants—hydroponic, aeroponic, or aquaponic. The following information describes these three growing systems:

Hydroponics:

The predominant growing system used in vertical farms, hydroponics involves growing plants in nutrient solutions that are free of soil. The plant roots are submerged in the nutrient solution, which is frequently monitored and circulated to ensure that the correct chemical composition is maintained.

Aeroponics

The National Aeronautical and Space Administration (NASA) is responsible for developing this innovative indoor growing technique. In the 1990s, NASA was interested in finding efficient ways to grow plants in space and coined the term “aeroponics,” defined as “growing plants in an air/mist environment with no soil and very little water.”

Aeroponics systems are still an anomaly in the vertical farming world, but they are attracting significant interest. An aeroponic system is by far the most efficient plant-growing system for vertical farms, using up to 90% less water than even the most efficient hydroponic systems. Plants grown in these aeroponic systems have also been shown to uptake more minerals and vitamins, making the plants healthier and potentially more nutritious.

Aquaponics

An aquaponic system takes the hydroponic system one step further, combining plants and fish in the same ecosystem. Fish are grown in indoor ponds, producing nutrient-rich waste that is used as a feed source for the plants in the vertical farm. The plants, in turn, filter and purify the wastewater, which is recycled to the fish ponds.

Although aquaponics is used in smaller-scale vertical farming systems, most commercial vertical farm systems focus on producing only a few fast-growing vegetable crops and don’t include an aquaponics component. This simplifies the economics and production issues and maximizes efficiency. However, new standardized aquaponic systems may help make this closed-cycle system more popular.

Vertical farming systems can be further classified by the type of structure that houses the system.

Building-based vertical farms are often housed in abandoned buildings in cities, such as Chicago’s “The Plant” vertical farm that was constructed in an old pork-packing plant. New building construction is also used in vertical farms, such as the new multistory vertical farm being attached to an existing parking lot structure in downtown Jackson Hole, Wyoming.

Shipping-container vertical farms are an increasingly popular option. These vertical farms use 40-foot shipping containers, normally in service carrying goods around the world. Shipping containers are being refurbished by several companies into self-contained vertical farms, complete with LED lights, drip-irrigation systems, and vertically stacked shelves for starting and growing a variety of plants. These self-contained units have computer controlled growth management systems that allow users to monitor all systems remotely from a smart phone or computer.

What Are the Pros and Cons of Vertical Farms?

Dickson Despommier, in his book The Vertical Farm: Feeding the World in the 21st Century, listed a number of environmental and social benefits of vertical farming. The following is an adaptation of Despommier’s major points:

• Continuous Crop Production—Vertical farming technology can ensure crop production year-round in non-tropical regions. And the production is much more efficient than land-based farming. According to Despommier, a single indoor acre of a vertical farm may produce yield equivalent to more than 30 acres of farmland, when the number of crops produced per season is taken into account.
• Elimination of Herbicides and Pesticides—The controlled growing conditions in a vertical farm allow a reduction or total abandonment of the use of chemical pesticides. Some vertical farming operations use ladybugs and other biological controls when needed to deal with any infestations.
• Protection from Weather-Related Variations in Crop Production—Because crops in a vertical farm are grown under a controlled environment, they are safe from extreme weather occurrences such as droughts, hail, and floods.
• Water Conservation and Recycling—Hydroponic growing techniques used in vertical farms use about 70% less water than normal agriculture (and aeroponic techniques, which involve the misting of plant roots, use even less water).
• Water Conservation and Recycling—Hydroponic growing techniques used in vertical farms use about 70% less water than normal agriculture (and aeroponic techniques, which involve the misting of plant roots, use even less water).
• People Friendly—Conventional farming is one of the most hazardous occupations in the United States. Some common occupational hazards that are avoided in vertical farming are accidents in operating large and dangerous farming equipment and exposure to poisonous chemicals.

In spite of these perceived advantages of vertical farms, some agricultural experts are skeptical that the costs and benefits will pencil out. Some think that expensive urban real estate in many cities may rule out vertical farms (although using abandoned warehouses or environmentally contaminated sites may help the economics). And the high electricity usage to run lighting and heating/cooling in a vertical farm impacts the economics. Below is a summary of the perceived disadvantages of vertical farming:

• Land and Building Costs—Urban locations for vertical farms can be quite expensive. Some existing vertical farms are based in abandoned warehouses, derelict areas, or Superfund sites, which can be more economical for construction.
• Energy Use—Although transportation costs may be significantly less than in conventional agriculture, the energy consumption for artificial lighting and climate control in a vertical farm can add significantly to operations costs.
• Controversy over USDA Organic Certification—It is unclear if or when there will be agreement on whether crops produced in a vertical farm can be certified organic. Many agricultural specialists feel that a certified organic crop involves an entire soil ecosystem and natural system, not just the lack of pesticides and herbicides.
• Limited Number of Crop Species—The current model for crops grown in vertical farms focuses on high-value, rapid-growing, small-footprint, and quick-turnover crops, such as lettuce, basil, and other salad items. Slower-growing vegetables, as well as grains, aren’t as profitable in a commercial vertical farming system.
• Pollination Needs—Crops requiring insect pollination are at a disadvantage in a vertical farm, since insects are usually excluded from the growing environment. Plants requiring pollination may need to be pollinated by hand, requiring staff time and labor.

Conclusion

Vertical farms in urban areas are a relatively new phenomenon, but interest in this approach is growing, and the number of vertical farms in the United States is expanding every year but in India it is still on experiment level. There are several variations of vertical farms being tested throughout the world, and new innovations and technology will likely increase the energy efficiency and profit margins of these farms in the future.

In the near term, most vertical farms will focus on high-return and short-rotation crops such as salad greens, with nearby restaurants often buying all of the production. Whether vertical farms will become more widespread in future is uncertain, but the innovative vertical farms currently under construction in different parts of the world or already in production are being closely observed by urban planners and the sustainable agriculture community.