Special considerations for walls
Lighting is often required for green walls positioned in low light exposure areas. Many green walls are installed within non-lit areas. Lighting green walls is highly specialised, requiring the services of a lighting designer or engineer. Plants require very specific lighting quantities and qualities to photosynthesise, grow, flower and develop appropriately. Tropical and subtropical green wall installations can generally survive in lower light conditions than Mediterranean, temperate plantings. Extensive knowledge of horticulture and design of green wall systems is needed to choose the right species for the light levels available on-site.
Another consideration for green wall installations is air movement around the foliage. This is important to help prevent fungal growth, and additional ventilation may be needed to ensure sufficient air movement for indoor walls. Outdoor walls usually create their own microclimate that creates enough air movement, but in very sheltered positions attention should be given to this issue.