The use of green walls in the urban environment - also known as living walls, bio-walls or vertical gardens - is an increasing 21st-century design trend and a feature of both interior and exterior spaces. Widely featured in workspaces, foyers, shops and restaurants, green walls are visually pleasing and appeal to our innate love of nature. The notion of biophilia is more and more recognised as an important design tool. Introducing natural elements into artificial environments has been shown to lift people's mood, increase productivity and reduce stress. In addition, with supporting technologies, they are green also in an environmental sense, contributing to natural air purification, cooling and humidification as well as they act as noise absorbers.
ERCO has now produced a whitepaper which provides guidance and advice on lighting green walls, a form of illumination which has very specialised requirements. Based on the latest findings and research, 'The perfect lighting for green walls' outlines all the key considerations involved and responds to the most frequently asked questions.
As well as water and nutrition, the right kind of lighting is essential if plants are to survive and thrive. It is crucial both the lighting approach – illuminance, light distribution, light exposure, colour temperature and rendering – and the choice of luminaires. What is important in this context is the balance between science and aesthetics, considering both the needs of plants and their visual appearance in an architectural space.
For example, plants especially need the orange and red range of the light spectrum, plus blue light, to carry out photosynthesis (the process by which green plants use sunlight to synthesise nutrients from carbon dioxide and water). However, only a source that also includes the green range of the spectrum and has good colour rendering is essential for a natural and attractive impression of green walls in architectural surroundings. It is also crucial to provide uniform light levels across the vertical surface to create the best conditions for the even, steady growth of plants. While downlights and spotlights might conventionally be used in these spaces, they will not provide the correct distribution. On the contrary, wallwash fittings are ideal for this application.
The whitepaper provides a comprehensive, detailed guide to all these aspects of lighting green walls, including visual examples and practical tips. It also examines areas such as calculating the location of luminaires, the optimum length of exposure to light, and more technical considerations such as the measurement of photosynthetic photon flux (PPF), the quantity of photons emitted by a light source that are relevant for photosynthesis and chlorophyll production. Suitable luminaire types are examined, and a glossary of relevant technical terms is provided, as well as a references list and a useful checklist for specifiers.
Photograhy by Jackie Chan, Murray Harris Photography P/L and Sebastian Mayer courtesy of ERCO GmbH