Controlled-environment agriculture is a technology-based approach toward food production. The aim of CEA is to provide protection and maintain optimal growing conditions throughout the development of the crop. Production takes place within an enclosed growing structure such as a greenhouse or building. Plants are often grown using hydroponic methods in order to supply the proper amounts of water and nutrients to the root zone. CEA optimizes the use of resources such as water, energy, space, capital and labor. CEA technologies include hydroponics, aeroponics, aquaculture, and aquaponics. Different techniques are available for growing food in controlled environment agriculture. The more viable option is vertical farming. Vertical farming has the ability to produce crops all year round in a controlled environment, with the possibility of increased yield by adjusting the amount of carbon and nutrients the plants receive. In consideration to urban agriculture, controlled-environment agriculture can exist inside buildings that already exist, such as repurposed abandoned buildings.
CEA facilities can range from fully 100% environmentally controlled enclosed closed loop systems, to fully automated glasshouses with computer controls for watering, lighting and ventilation, to low-tech solutions such as cloches or plastic film on field grown crops and plastic-covered tunnels. CEA methods can be used to grow literally any crop, though the reality is a crop has to be economically viable and this will vary considerably due to local market pricing, and resource costs.
Motivation
Crops can be grown for food, pharmaceutical and nutriceutical applications. It can also be used to grow algae for food or for biofuels. Using CEA methods increase food safety by removing sources of contamination, and increases the security of supply as it is unaffected by outside environment conditions, and by eliminating seasonality create stable market pricing which is good for farmer and consumer alike. CEA is used in research so that a specific aspect of production can be isolated while all other variables remain the same. Tinted glass could be compared to plain glass in this way during an investigation into photosynthesis. Another possibility would be an investigation into the use of supplementary lighting for growing lettuce under a hydroponic system. A February 2011 article in the magazine Science Illustrated states, "In commercial agriculture, CEA can increase efficiency, reduce pests and diseases, and save resources. ... Replicating a conventional farm with computers and LED lights is expensive but proves cost-efficient in the long run by producing up to 20 times as much high-end, pesticidee-free produce as a similar-size plot of soil. Fourteen thousand square feet of closely monitored plants produce 15 million seedlings annually at the solar-powered factory. Such factories will be necessary to meet urban China's rising demand for quality fruits and vegetables."
Industry
As of 2018, an estimated 40 indoor vertical farms exist in the United States, some of which produce commercially sold produce and others which are not yet selling to consumers. Another source estimates over 100 startups in the space of 2018. In Asia, adoption of indoor agriculture has been driven by consumer demand for quality. The Recirculating Farms Coalition is a US trade organization for hydroponic farmers. AeroFarms, founded in 2011, raised $40 million in 2017 and reportedly opened the largest indoor farm in the world in Newark, New Jersey in 2015; by 2018 it built its 10th indoor farm. Plenty, Inc., based out of South San Francisco, raised over $200 million in 2017.
Economics
The economics of indoor farming has been challenging, particularly the price of electricity, and several startups shut down as a result. Advances in LED lighting have been one of the most important advances for improving economic viability.
