Green Wall Gardens - Living Walls & Vertical Gardening

In a perfect world, there’d be plenty of room for gardens, greenery and foliage to exist in harmony with us as we go about our day-to-day lives. However, urbanisation and increasing levels of population density in big cities have forced urban planners to get creative. You may already be familiar with the concept of the ‘living wall’ or have seen it in the wild. It can be initially jarring to walk down a bustling city street - or through an airport lobby - and come face to face with a lush, thriving garden of sorts. We expect gardens to be horizontal; the opposite doesn’t seem to have any logic! And yet these kinds of arrangements have been shown to have a hugely positive effect on people’s mental health and mood, not to mention a host of environmental benefits.

The living wall or vertical gardening concept isn’t just for urban planners or creatively-minded architects, though. The same principle can be applied by a single individual who maybe lives in a small flat with little or no outdoor space to use for growing plants. There are a number of options and styles that can be utilised to create a vertical garden in the home or on an outside wall. As long as you pay attention to some important guidelines, you can get creative with it and bring some aesthetic charm to your living space. Some of the ways you can do this include arranging your plants in patterns or by adding decorative rocks and accessories to the lay-out.

What are the Benefits of a Living Wall?

In Urban Environments:

• They can have a stress-reducing effect and improve mental well-being. A survey related to the ‘Garden Gate’ in Heathrow Airport, one of Europe’s busiest airports, showed a marked increase in customer satisfaction. Whether in healthcare settings or in bustling malls, they can create a sense of comfort or sanctuary.
• Vertical gardens can mitigate the effects of air pollution, absorbing harmful toxins, carbon dioxide and volatile compounds. Air pollution is a serious issue in our cities; in places like London it’s frequently bad enough to trigger official ‘alerts’, while long-term exposure can lead to all kinds of health effects. This pollution can be exacerbated when it gets trapped between tall buildings. Plants and greenery have been shown to have the ability to filter out much of this pollution.
• Reduced energy costs: Maybe a lesser-known effect, but a vertical garden on the outer wall of a building can improve insulation in cold weather as well as having a cooling effect during hot spells of weather.
• Biodiversity: Living walls in urban areas can attract all kinds of insects, wildlife and pollinators. This can have an immeasurable positive effect in what would otherwise be a bit of a ‘concrete jungle’, as well as supporting a healthy ecosystem.
• Aesthetics: Much like street art or sculptures, green walls bring character, beauty and vibrancy to the city landscape. Some of the more famous examples of green walls have become bona fide places to visit.
• Cooling: Green walls can reduce internal temperatures in high-rise buildings by around 5°C.

For the Individual:

You may be wondering, ‘Is it practical for me to set up my own living wall?’, and the answer is yes, it certainly can be. Among the benefits you can pretty much include all of the above points and just apply them to your own home setting (although you probably don’t want to attract too many insects into your living room!). Then there are also some extra benefits:

• Gardening in Small Spaces: One of the knock-on effects of our long-running housing crisis - as well as urban living in general - is that a lot of people simply don’t have the space to propagate a garden. They might even struggle to find space for a few pots! Vertical gardening can work in compact spaces such as flats or apartments, allowing you to grow attractive plants as well as edible crops that can adapt to the system.
• Noise Levels: Loud neighbours? Living near a school, motorway or construction site? Plants and foliage can have a noise-damping effect, absorbing sound waves. Studies have suggested that some green walls can reduce ambient noise by up to 40 decibels. This might even work in your favour if you like to listen to loud music (and who doesn’t?) or play an instrument.
• Cooling Effect: Unlike brick walls for example, green walls don’t absorb heat and transfer it back outwards during the night. This means that they can have a cooling effect during hot spells in summer, something that can be invaluable in places like the UK and Ireland where we don’t really have a culture of home air conditioning (yet!). Evergreen or native plants are useful for their cooling properties in this set-up, and they will need less maintenance.
• Stress-Reducing
• Reduced Energy Costs
• Aesthetics
• Mitigate Pollution

How To Set Up A Green Wall
Green walls can be freestanding or they can be attached to an interior or exterior wall. There’s a whole array of styles; how suitable they are for certain plant varieties can depend on the structure, the space available for planting and how they function. The living wall can take the shape of a single panel or it can cover almost the entire height of the wall. They can also always be scaled up as you get more confident and successful with the experiment.

Figure out your daylight and humidity levels if you’re going to be setting up the wall indoors. It may be necessary to use grow lights if you don’t get enough natural sunlight. Alternatively you can concentrate on growing more shade-tolerant plants. Herbs and salads make for good choices when starting out with a green wall set-up: basil, rosemary, chives, lettuces; while peas, tomatoes and squash are good climbing varieties to go for. Go for good quality potting soil if using a soil medium; this can be combined with materials such as clay pebbles, perlite or vermiculite. With succulents that will be growing for years, it’s advised to use a mix with a high mineral content.

For obvious reasons it’s best to select compact plants when deciding what to plant or place in your green wall. They will also need a relatively shallow root system to thrive. You will also need to keep on top of pruning and maintaining, as you want to keep this growing environment neat and tidy, and discourage overcrowding of plant foliage. Adding plants to your green wall as plug plants (rather than growing from scratch) can be a good idea, as it allows them to get some strong roots established before moving to a vertical growing environment.

Green Wall Types
As mentioned above, there’s a lot of room for individuality when it comes to vertical gardening, but it’s useful to separate them into two main ‘types’. Within these main types, there’s a lot of room for variation, and anyone should find something that will suit their individual tastes, circumstances or budget.

Green Facades
This is where climbing plants are allowed or encouraged to grow up along the facade of a building. They are usually planted in soil or a raised bed planter at the base of the wall. Green facades can be separated into ‘direct greening’ (where the climbing plant attaches to the building facade itself) or ‘indirect greening’ (where it attaches to a trellis or framework, opening up a pocket of space between the foliage and the building facade). Self clinging climbers will suit the former while plants with vining growth and tendrils will avail of the second. Green facades can be used on external walls as well as balconies and terraces. Climbing plants will benefit from a deep and fertile soil.

Living Walls
Living walls - or vertical gardens - are structures that provide growing space for plants, as well as growing medium within the structure. The vertical garden can be of any size or shape. They also commonly include an inbuilt system for providing water and nutrients for the plants. This can be something such as dripper pipes connected to a reservoir at the base. Careful design, protective materials and waterproof membranes ensure that the wall you attach your vertical garden to won’t be affected by water damage or damp (as long as you use it correctly).

Some examples of living wall setups include:

• Felt Pockets: A relatively lightweight and flexible variation that uses felt pockets or planters. Within these pockets is space for the plant as well as growing medium like soil, coco coir, perlite etc.The felt material used in a vertical garden planter is typically made of recycled plastic or synthetic fibers, and is designed to hold moisture and nutrients. The felt will also be permeable, allowing water to flow through the material and irrigate the plants evenly. The pockets typically allow excess water to drain away or run off (drip trays should be used and regularly emptied indoors).

• Modular Panel Design: This kind of living wall features panels or modules with pockets of space for your plants. Plants can be pre-grown in the module before it’s installed, but this is optional. The setup lends itself to arranging your plant display in aesthetically pleasing patterns. Modular living walls tend to be heavier.

• Hydroponic Living Wall Systems: Hydroponic living walls don’t use soil as a growing medium; instead the plants are grown with a water-based solution that also delivers minerals and nutrients. Hydroponic living walls can be more complex, especially when it comes to irrigation. Root rot can be a risk if plant roots are sitting too long in damp pockets, so it’s important to monitor the system and watch out for overwatering or signs of nutrient deficiency. One method is to have moisture-loving plants at the base of the vertical garden, as these pockets will stay wet for longer.

Some famous examples of green walls and vertical gardening
If you’re at all in doubt about what can be achieved through vertical gardening, there are some striking examples of urban green wall set-ups. They are reminiscent of the future that we once dreamt up in sci fi films such as Blade Runner (before the internet adjusted our sense of futurism). Indeed, there are fully-fledged ‘green cities’ being designed in China.

• Bosco Verticale

These two residential towers in Milan, Italy have over 900 trees growing throughout the facade. It was designed by Boeri Studio with input from horticulturalists and botanists.

• CaixaForum Museum

This art gallery in Madrid features a vertical garden that covers 4951 square feet, with over 250 different species. It has a hydroponic setup and was designed by French botanist Patrick Blanc.

• Terminal 3, Changi Airport, Singapore

A vertical garden that spans the length of three football fields (!) and features an array of layers and textures. It has an automated irrigation-and-fertiliser system that delivers precise measurements.