There is an increase in importance of green walls and green façade in building design elements as they do improve the environmental impact of a building whist adding a touch of beautiful aesthetics. An ever growing climate change challenge have led the architects and builders to adapt sustainable building designs that has the potential to reduce energy demand and minimize environmental impact. Green walls, Green Façade or living walls is an architectural and gardening technique that basically implies walls covered with plants, reflecting our desire to be surrounded by nature even in concrete jungle. The main difference between a green façade and green wall is the structure that the plants grow on. Creating greenery over a façade is a task that requires certain elements of engineering, architecture and irrigation, selecting the right system is one of the most crucial step in the installation of green façade. A combined planning and effort of the architect and horticulture specialist is needed for the planting plan for a vertical garden, which can be done after taking into account all various factors such as sustainability, growth pattern and maintenance requirements.
 
Green walls (also known as plant walls, living walls or vertical gardens) have become a rising new trend of built environments in recent years. Incorporating living nature into urban environments not only looks much more inviting, but also has a number of other benefits and purposes. Architects are collaborating more and more creatively with botanists to create vertical gardens and true living walls in which plants can thrive without soil—enhancing the architecture and the environment.
Green Façade on the other hand is a wall that supports the branch system of plants with soil at the base of the wall, planted in ground or container. In this system the framework is not integrated with growing medium, primarily providing support to the growth of plants on the wall structure. One of the advantages of green façade is a considerable reduction in load bearing requirements. The difference between green walls and façade is that green walls are generally more expensive and complex than green walls.
 
HOW DO WE DEFINE A GREEN WALL…?

Green walls refer to green infrastructure where a vertical garden or vegetation is installed on the exterior of building  wall. It contains a growing medium across the structure which means the soil and water delivery mechanism is interpenetrated into the wall in order to grow plants and vegetation. This is a technique in which plants grow on a vertical surface over the building façade in a controlled pattern. Green walls are vertical structures that have different types of plants or other greenery attached to them. The greenery is often planted in a growth medium consisting of soil, stone, or water. Because the walls have living plants in them, they usually feature built-in irrigation systems. This technique works well with plants having a shallow root structure such as moss, fern, herbs and vines. The hydroponic method can also be applied while designing a green 
wall, as the name suggests there is no soil required instead the use of a water nutrient mix as a growing medium is installed to provide stabilized continuous feeding to the plants through closed irrigation system.
The main elements that are needed for the construction green walls  are
    The plants
    The planting media
    Support structure
    Irrigation system

The concept of green walls is not relatively new, there have been proof of its use since centuries in construction of buildings for providing shade to the walls and protecting them from wind

The original inception of vertical vegetation or green walls can be traced back to somewhere between 600 B.C. to 800 B.C. to the HANGING GARDENS OF BABYLON (the corresponding image is a reference to the statement).

In many northern countries the vegetation was integrated into the building tradition. Here a turf or a top layer of soil was used as façade material it was termed as sod, which provided thermal insulation against severe weather conditions. One of the few disadvantages though being highly susceptible to water penetration.

The idea of a “living wall” was fully realized in 1986, when botanist Patrick Blanc, working alongside architect Adrien Fainsilber and engineer Peter Rice, completed the first large-scale indoor living wall at the Cité des Sciences et de l’Industrie science museum in Paris. As Blanc said:
“Plants don’t need soil because it is merely the mechanical support. Only water and the minerals dissolved in it are essential to plants, together with light and carbon dioxide to conduct photosynthesis. Wherever water is available all year long, as in tropical forests or in temperate mountain forests, plants can grow on rocks, tree trunks, and slopes free of the ground. For instance, in Malaysia 2,500 species grow without any soil.”

Green walls in Modern Times

•    Societies are in a need for making a conscious choice to switch to a more sustainable way of life. Design, construction, and maintenance of buildings have a tremendous impact on the environment and the natural resources. All around the world, a huge amount of buildings is being constructed with many more to be done. Nowadays urban areas are becoming unhealthier for habitation due to being overcrowded, pollution and increase in air temperature. Green open spaces have been getting depleted from urban cities due to lack of available spaces. This problem has resulted in adaptation of a sustainable approach by creating a balance between environment and architecture. Climate changes and energy crises have lead the architects towards a newer approach and one of the approach is facade integrating greenery on building has a positive impact on the city and its inhabitants

CaixaForum Museum is a modern art gallery located in Madrid, Spain. The massive outdoor vertical garden was designed and created by French artist and botanist Patrick Blanc and was the first of its kind in Spain. The vertical garden is 4951 square feet and has over 15,000 plants of 250 different species, which survive Madrid’s hot summers and cold winters alike thanks to hydroponics (a method of growing plants without soil).

The external living wall of the Musée du Quai Branly in Paris has become iconic since its introduction in 2004, and understandably so: Its striking green color covers an entire facade of the building and stands in stark contrast in the Parisian urban landscape. It was originally created by Patrick Blanc but had to undergo a restoration in 2017 and 2018.

One of the largest living walls in all of the United States, the facade of Gardenhouse in Beverly Hills has been designed to look, from afar, like a verdant hill supporting a small village. Gardenhouse, designed by architecture firm MAD and completed in August 2020, is comprised of ground-floor commercial units topped by 18 private residences that seem to sprout from the living wall.

Located at Universidad del Claustro de Sor Juana, one of Mexico City’s largest universities, this green wall is a prominent work of art in the historic center of the city.

 
 
Advantages of Green Walls AND Green Facades
There are many advantages to having green walls livening up a space. First of all, the visual benefits of the living wall cannot be ignored. The eye-catching pieces can make a big impact decorating an urban environment made out of concrete and bricks, thus offering alternatives for urban agriculture, gardening, and indoor decor.

•    Green facades lose less heat and also causes evaporation which makes the climate cooler. For centuries certain creepers have been used to adorn building facades.
•    There is an increase in adaptation of vertical vegetation and vertical gardening  in larger urban cities in recent times as it provides the surrounding areas with a cooling defect whilst taking up dry little space.
•    Plants protect the building against environmental damage resulting from heavy rains and also from solar radiations as the façade absorbs less heat. It helps to keep the walls dry during monsoon, it can be said that green walls have a tempering effect on the temperature during summers and winter.
•    Vertical greening can provide a cooling potential on the building surface, which is very important during summer periods in hot climates

.•  Green façade helps in moderating the temperature around the building, therefore improving living conditions. If a city is constructed following a green façade architectural structure it will help in moderating the micro climate around the city. Integration of greenery to building façade can improve the air quality in cities.
•    During the day plants extract carbon dioxide, carbon monoxide and many other toxins from the air during photosynthesis, resulting in significant reductions in CO2 levels in well vegetated urban areas. The photosynthesis process that is being carried out by the plants on the façade provides cleaner air to breathe for the habitants.
•    Integration of green walls also serves as a cover for old, ugly or worn out building spaces and improves its appearance aesthetically.
•    Large areas of greenery help to suppress dust particles; improving air quality around construction sites and busy highways. This may lead to a reduction in respiratory illness.
•    By bringing nature into the hearts of our cities, we remind ourselves of our place in—and our responsibility for—the world. We create a sense of environmental stewardship—and nothing is more essential if we are to live in thriving urban environments. There is a great sense of value in this and organizations that enrich the spaces around us will benefit from this value.