Vertical Gardens - the Ultimate in Organic Architecture
Today, vertical gardens come in a wide variety of forms, from simple proprietary planting pockets or pots, to highly sophisticated purpose-built planting structures. They can also be applied both internally and externally.
Biophilia is defined as a love of life and the living world and describes humanity’s innate tendency to seek connections with nature and other forms of life.
Vertical gardens are biophilic designs that integrate natural elements, materials and forms into architecture. Often incorporating a wide range of plants, research has demonstrated that a mix of species can have a potent biophilic effect, providing measurable physical and physiological benefits including:
- reduced stress levels
- enhanced cognitive function and creativity
- a deeper sense of happiness and well-being
- an ability to heal faster.
For those of us living in urban environments, 90% of our lives are spent indoors learning, working, socialising, relaxing and sleeping. Living in air-conditioned environments that contain toxins such as formaldehyde, VOCs, trichloroethylene, carbon monoxide, benzene, toluene and xylene, this is a strong mix that can have a serious impact on our health.
Vertical gardens reduce the carbon footprint of a building by filtering these pollutants and carbon dioxide out of the air. A recent NASA study concluded:
- plant leaves and root micro-organisms can remove toxins from the air within buildings
- certain tropical species are more efficient than others
- increased oxygen released from plants helps keep people awake and alert.
External vertical gardens can contribute to reducing this effect and make our future cities more sustainable by:
- reducing absorption of thermal energy transmitted through building walls to inner surfaces.
- decreasing the need for air-conditioned cooling systems.
- reducing air temperature
- balancing humidity levels
- increasing airflow.
Internal vertical gardens have been demonstrated to:
- increase wall sound absorption co-efficiency
- enhance speech privacy
- improve ambient noise levels of office environments
Agribusiness, the commercial production of leafy greens, herbs or plant seedlings using multi-level growing systems is rapidly expanding around the world.
These are typically grown as vertical gardens in a fully enclosed and climate-controlled environment, offering a simple way to boost growing space.
Since they don’t rely on fertile arable land and can be established in any climatic region globally, irrespective of seasonal daylight hours or extremes in temperature, they offer much greater flexibility than traditional farm practices.
This avoids seasonal cropping limitations increasing production, and removes external pressures such as disease, pest or predator attacks which cause crop losses in traditional farming.
Produce quality is also consistent and reliable.
- Be capable of supporting the load of the entire system including the plant containers and support structure, the growing medium (soil), the plants themselves, irrigation and lighting.
- This load needs to be based on a saturated garden, as water considerably increases the weight of the installation.
- Waterproofing to protect the host wall from the majority of irrigation water flow and avoid the risk of any long term water damage.
- Orientated and located to provide the most favourable growing conditions.
Consideration needs to be given to mixing plants that enjoy the same growing environment, and that have a similar growth rate to avoid a more aggressive plant outgrowing and overshadowing its neighbours.
Gravity also needs to be considered as water will drain down through the garden from the top to the bottom, resulting in drier conditions at the upper tiers, and potential for waterlogged plants at the base.
Plant selection is also based on consideration of many other factors including:
- location of the wall
- orientation of the wall faces
- amount of sunlight and/or natural light
- amount of shade
- type of vertical garden (internal or external)
Certain plants better suit different environments. Horticulturalists specialising in vertical gardens can be consulted to recommend suitable aesthetic and practical plant palettes for the particular application.
- Porosity and drainage. It is generally desirable for the growth medium to hold some moisture, however if it becomes waterlogged, it can impact on the plants health promoting funguses and root rot.
- Weight. Dry and wet weights can vary significantly and may impact on the strength of the support structure or host wall.
- Nutrients. Plants can receive their required nutrients through fertilised soil, or hydroponically through the water they are fed.
- Long term plant health.
- Water flow is kept within the confines of the vertical garden.
- Lowest water consumption rates.
The Irrigation system needs to account for the geographic location, humidity, temperature, sunlight, shade, wind and the following factors:
- Amount of water each plant requires.
- Frequency of watering
- Fertilisation requirements.
- Minimal excess water drains through the garden requiring collection or drainage.
Walls that receive little direct sunshine generally thrive as vertical gardens, whilst western facing walls exposed to afternoon sun are the most challenging, requiring hardy plants.
Indoor plants are extremely sensitive to light and require a carefully designed and constructed environment to survive. If a vertical garden doesn’t receive adequate natural sunlight or ambient light, artificial lighting will be required to support photosynthesis which is vital to plant life.
This is typically provided by the installation of Metal Halide Lamps which emit UV light, however as this is a stark unattractive light source, it is recommended that the lighting system operates outside of business hours.
Plants are subject to a circadian rhythm and need periods of darkness balanced with light to survive, so it is important to ensure the correct timing of artificial lighting takes this into account.
Creative use of effect lighting can also enhance the dramatic visual aesthetics of a vertical garden.
Ongoing maintenance typically involves;
- removal of shedding foliage
- trimming of plants
- testing the irrigation system
- testing grow lights
- refilling fertiliser
- pest management
- seasonal refurbishments of plants
Vertical gardens if well designed, installed and maintained won’t just look good, but will also provide numerous positive benefits to your living environment.