What are the different types of vertical farming systems?
Answer: 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:1. 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.2. 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. 3. 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. 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. To learn more, consult the ATTRA publication Vertical Farming. This publication introduces commercial-scale vertical farming and discusses the recent growth of vertical farms in urban areas. It describes the major types of vertical farms and discusses environmental issues with vertical farms. The publication includes a list of the major vertical farms in the United States and lists further resources.