A cultivation wall or green wall is a vertical installation covered with plants of various species that are grown in a special structure giving the appearance of being a garden but vertically, hence it is also known as vertical garden. The plants are rooted in compartments between two sheets of fibrous material anchored to the wall. Water supply is provided between hoses and many species of plants are grown. Bacteria in the roots of plants metabolize impurities in the air such as volatile organic compounds.

Active walls or green walls join the air circulation system of the building. Fans blow air through the wall and it is then recirculated through the building. Some active walls have glazed surfaces to make the effects of airflows more predictable. 'Inactive' or 'passive' walls do not have mechanized air circulation. Instead, they are open to promote, as far as possible, the free circulation of air.

Grow walls are a form of urban agriculture or urban gardening. They are usually undertaken as an artistic work due to their beauty. Sometimes it serves to help cure sick building syndrome, and in any case, increase oxygen levels in the recirculation air.

It is also a means of reusing water, at least utilitarian water. Plants can purify contaminated water (gray water) by digestion of dissolved nutrients. Bacteria mineralize organic components to make them available to plants.

Grow walls are very practical for cities, especially in vertical areas or locations with very little space. Also for arid areas, since the water circulating in the vertical wall is less and can be recycled. In hot, arid areas, these walls can form part of the external walls of a building, and can cool them.