As of 2016, there were 2.3 million square feet of indoor farms worldwide. This area is expected to grow substantially, with estimates ranging between about 8.5 million square feet to 16.55 million square feet by 2021. The average yield per acre of vine crops, such as tomatoes, and greens grown in indoor farms is over ten times higher than that of outdoor farms, demonstrating that indoor farming is a much more efficient use of space compared to traditional outdoor farms.
Although there are dozens of different crops grown in indoor farms, from flowers to lettuce, the most lucrative by far is cannabis, which generates about 380 U.S. dollars in revenue per pound, followed by herbs and microgreens at about 13 dollars per pound. However, in terms of average annual revenue per square foot of crop, vine crops bring in the most revenue with 175 U.S. dollars per square foot per year.
Among all innovations in the indoor farming industry, vertical farming is one of the most influential. Vertical farming is, as its name suggests, the practice of growing crops in vertically stacked layers. It has been praised as a much more efficient use of space than traditional farming which uses massive areas of open land. Vertical farming could be implemented in major metropolitan areas, or even in shipping containers. In 2016 the global vertical farming market was worth about 1.5 billion, and it is projected to grow to about 6.4 billion dollars by 2023.