What is CEA and what advantages does it bring?
Controlled Environment Agriculture (CEA also called Indoor Farming) is still in the process of defining its own identity. How much the various methods really do (and will in future) have in common in order to justify a common term to describe them, remains to be seen. For the present the term is mainly used to describe the growing of crops in an environment of which certain aspects are controlled. The controlled aspects can include lighting, temperature, humidity, irrigation, fertigation and other factors that influence plant physiological responses.
It can take place in
Greenhouses → controlled-climate structures with walls and roof made out of materials that are transparent. If the structure is located on a roof it is a rooftop greenhouse. Greenhouses all utilize sunlight, however they can have additional artificial lighting
Indoor Farms → crop production under artificial instead of sunlight. This can be done on a number of scales, from a small box to whole warehouses or factories, specially constructed or converted. Old Shipping Containers (Container Farms) are especially popular. They can consist of a single container or systems with up to 64 connected ones. Another special case are Vertical Farms where the crop production makes use of vertical space. Crops can be stacked horizontally or grow in tall towers.
High Tunnels → crops covered by a protective canopy to protect them against the elements (not small backyard hobby tunnels). Artificial lighting is nowadays rarely included, except for experimental cases.
The obvious question is why? Why should it make sense to build more or less expensive structures and have to work hard to provide crops with everything they need when it is perfectly possible to grow crops out in nature? On cheap land, with free sunshine, nutritious soil and ideally even irrigation via rain.
Well for once population growth, migration urbanization, energy- and water use, the availability of arable land and the effect of pesticides, heavy machinery and other side effects of conventional agriculture, not to mention climate change, all point to future disruptions of our food supply resulting in price spikes and scarcity. Despite advances in plant genetics, agricultural technologies and farming methods, open field farming is reaching its limits, esp. in the production of fruits and vegetables. Apart from the immediate effects of pesticides, open field farming also contributes to the depletion of fresh water sources, and nitrogen loading of waterways. So the world does need something new.
Advances in environmental controls, substrates, growing systems, artificial lighting, robotics and other forms of automation have made CEA such a viable alternative. Even though it cannot be used yet to mass produce the most important staple crops, like wheat, rice and potatoes the method can already be a gamechanger in the production of vegetables and salads.
Vegetables and salads grown indoors under controlled conditions offer the promise of a consistent supply of post-organic and pesticide-free food, free of the disruptions of climate change. They can be grown already twice as efficiently as in open field and produced near or even inside cities. All over the world. Or even in space.