Globally, more people live in urban areas than in rural areas, with 54% of the world’s population residing in urban areas in 2014. It is estimated that by the year 2050, the world’s population would increase to 10 billion, and close to 80% of human settlements would be concentrated in and around urban locations. This growing urban population will need access to healthy and nutritious food. To provide food to these urban-based inhabitants, vast areas of cultivable land might be required. But then again due to competition from sectors other than agriculture, researchers, experts, and planners are skeptical about the accessibility of such spread-out land parcels, particularly those around the prevailing and futuristic metropolitan agglomerations. This strong worldwide urbanization also puts a demand for producing vegetables in close proximity to the consumers. This gives us one of today’s major challenges. Land, water, chemical fertilizers, and energy are vital resources for food production. Only 1% of freshwater found on the earth is accessible or available for human usage. Nearly 70% of that water is used in agriculture mainly for irrigation. Reserves of fertilizers, that are crucial for the production of food, are running out. With agricultural land becoming scarcer and the need for producing closer to or even in the cities to shorten the supply chain, not always the best soil can be chosen for producing crops. In this critical condition, we have to identify some alternatives to produce the vegetable crops without using soil medium in urban and peri-urban areas where rooftop/terrace space is available abundantly. When grown on the substrate, the quality of underlying soil is not a consideration, since plants do not root in the underlying soil; water and nutrients are delivered directly to the crop via the substrate. Substrate cultures can even take place without soil, for example, on concrete floors in buildings.
Part of the book: Recent Research and Advances in Soilless Culture