A plant factory is a closed growing facility which helps in balanced and constant production of superior quality vegetables throughout the year. This kind of facility cultivates vegetables by artificially controlling the entire environment, i.e., temperature, light, humidity, culture solution, fertigation and carbon dioxide concentration; and thereby enabling growers to mass production of plants. Plant factory practices vertical farming which is producing food in vertically stacked layers, inclined surfaces or incorporated in various other structures. The modernized and latest techniques of vertical farming make use of controlled-environment agriculture (CEA) technology, in which all the possible environmental elements can be controlled. A few of the vertical farms use procedures analogous to greenhouses, where natural light i.e., the sun can be easily bettered with artificial lighting and metal-reflectors.

A few of the advantages of Vertical farming are –

Can be set up on non-farmland areas, e.g., vacant stores, industrial parks, etc.

Proficient of throughout-year production with stability

Work-friendly environment wherein even disabled as well as elderly people can work

Can hire novice farmers owing to light workload

Safe and superior-quality agricultural production with no or very minimum use of pesticide

Vertical farming is categorized into three types - Mixed-use skyscrapers, Despommier's skyscrapers and Stackable shipping containers.

Mixed-use skyscrapers – This concept was proposed and executed by architect Ken Yeang. He suggested that as an alternative to hermitically sealed mass-produced agriculture which plant must be cropped within open air, mixed-use skyscrapers for the purpose of climate control and consumption. This variant of vertical farming is dependent on personal and/or community use instead of extensive production along with distribution of plant life which aims to feed a complete city.

Despommier's skyscrapers – This theory of vertical farming surfaced in 1999 at the Columbia University. It encourages mass cultivation of plant life in skyscrapers for commercial purposes. The concept is quite similar to the mixed-use skyscrapers, except that these would predominately be sealed off from the rest of the world and would be operational with very minimum to no human interaction.

Stackable shipping containers – The concept of stacking recycled shipping containers especially in urban settings have become a latest trend. For example, Freight Farms develops a ‘leafy green machine’ which is a full farm-to-table system outfitted along with vertical hydroponics, climate controls, LED lighting, all within a 12m x 2.4m shipping  container.