Around 55 % of the world’s population live in cities with this number expected to increase to around 68 % by 2050 ( Haus von Eden). With the growth of the population, food security becomes a pressing issue. By 2050, the world’s population will grow to 9.7 billion people, which is estimated to be a 70 % higher demand for food (heise). Consequently, traditional agriculture is reaching its limits: with the consequences of climate change increasing, extreme weather conditions such as heavy rain and drought have a negative impact on yields. Additionally, the majority of cultivated grain is not used for human nutrition, but mainly for the production of feed for livestock. Through monocultures, the use of chemicals, overgrazing and sealing, more and more usable area for agriculture is lost (Soy; Bundesinformationszentrum Landwirtschaft). In Germany, more than 6 % of the total area is already sealed and around 73 hectares of land are lost every day for new settlement and traffic areas (GIZ). An approach to combating overpopulation, food shortages, megacities and climate change is a new concept of agricultural production called urban farming.
Conscious consumers want to shop locally and find out more about where, how and by whom their food is produced. Due to global imports, this is often difficult to understand. Urban farming reconciles living, working, producing and ultimately consuming in an urban area (Seawater). There are various types of urban farming: from guerrilla gardening or tree slice greening, district gardens and neighbourhood gardens, children’s farms and solidarity agriculture, intercultural gardens and women’s gardens to community gardens on roofs and vertical gardens on facades (speiseräume). Vertical gardening is probably the most efficient type of urban farming. This kind of agriculture is able to produce large quantities of food in a small area, 365 days a year (Bundesinformationszentrum Landwirtschaft). The plants grow upwards, for example in high-rise buildings, disused warehouses or on house facades. If the plants are also grown completely without natural sunlight, this is called indoor farming. For this purpose, so-called farm scrapers are grown on levels one above the other. These buildings are mostly equipped with a circular economy and hydroponics, which enables resource-saving and year-round production (Soy; Haus von Eden). LED light and nutrient solutions replace natural sunlight and soil. Methods such as hydroponics (planting without soil), aquaponics (a mixture of hydroponics and aquaculture, i.e. fish farming, in which process water from the fish farming system is also used to supply plants with nutrients) or aeroponics (roots of the plants hang in the air and are sprayed with water and nutrients) are used (Soy). These systems are particularly efficient and intensive, as they save space, the plants are optimally supplied with water and nutrients, grow quickly and give higher yields per unit area (Pflanzenfabrik).
Vertical farming could offer innovative solutions both for feeding the growing world population and for the ever-decreasing arable land (agrarheute). The list of the advantages of this new agricultural system is long: compared to traditional agriculture, which is globally responsible for a third of CO2 emissions, vertical agriculture uses 70 to 95 percent less water and over 90 percent less land, while 80 percent more is harvested per unit area (utopia; Columbia University). Additionally, it requires short transport routes, no use of pesticides and low consumption of water and fertilizer due to the closed cycle system as well as a year-round cultivation and harvesting (Soy). Especially in climatically disadvantaged areas, where vegetables and fruit have to be imported at a high cost, the transition to vertical agriculture makes sense; in these regions, vertical farms can be operated inexpensively – economically and ecologically – with solar energy (Bundesinformationszentrum Landwirtschaft). It can also be useful from a social point of view: for recreational activities, for generating an income or for obtaining food in areas with poor supplies (McCormick).
However, vertical farming is often criticized for its energy balance because of the high use of energy for LED lights. Vertical farming also lacks soil microorganisms, found in traditional agriculture, that are important for human intestinal health; instead, microorganisms and nutrients from irrigation have to be artificially added (utopia). Furthermore, without the cultivation with soil, food sourced from vertical production cannot be certified as organic since the principle of organic farming consists of soil-related production (Bundesinformationszentrum Landwirtschaft).
The market for vertical agriculture is still young, but is considered by investors to be a promising technology (Business Insider). Thus, many companies have already discovered the new model for themselves: The world’s largest vertical farm to date is in New Jersey, where AeroFarms produces more than 900 tons of food per year in 6,500 square meters of space, mainly for local supermarkets (utopia). In Germany, the Berlin start-up Infarm produces its vegetables directly for end consumers in supermarkets or restaurants. Temperature and light intensity are controlled completely autonomously, health status and growth of the plants are monitored via infrared cameras and for the harvest, an Infarm employee comes to the markets, places the plants in a shelf ready for sale and immediately installs new ones. Other start-ups such as Agrilution from Munich or neoFarms from Hanover are pursuing similar concepts (agrarheute). The German grocery retailer REWE opened Europe’s first green supermarket in May 2021. The store combines a supermarket, basil farm and fish farming under one glass roof. Around 1,100 cubic meters of wood store 700 tons of CO2, 800,000 basil plants grow annually using aquaponics, which receive excretions from the fish that REWE breeds on site as fertilizer. The building uses 100 % green electricity and rainwater for the roof farm, sanitary facilities, and cleaning of the market. The concept should be implemented in full or partially, depending on the property, for future buildings (REWE Group).
Prospectively, more efficient LED lighting and better cost management will create a fair economic competition between indoor farming and the outdoor production of food. However, consumers, technology and politics will determine how quickly innovative urban farming concepts will be competitive .
By Marie Klimczak