High tunnels are unheated, plastic-covered structures that provide an intermediate level of environmental protection and control compared to open field conditions or heated greenhouses.

A strict definition of a high tunnel does not exist, and the terminology may change depending on the structure's use.
"Hoop House" and "High Tunnel" are often used interchangeably. For example, a market farmer might grow an additional crop of sunflowers in a "High Tunnel" after first frost, whereas a nurseryman could over winter container-grown perennials in the same structure but call it a "Cold Frame". The same structure is also marketed to livestock operations for animal, feed, and equipment shelter.

High tunnels are used in many applications ranging from small gardens or farms to commercial agriculture

Commercial agriculture

Commercial Agriculture refers to a process of large-scale production of crops for sale, intended for widespread distribution to wholesalers or retail outlets. In commercial farming crops such as wheat, maize, tea, coffee, sugarcane, cashew, rubber, banana, cotton are harvested and sold into world...

to protect plants, animals or equipment by reducing the effect of environmental variables and offering limited environmental control.