Guide written by:
John, Passionate gardener, Cambridge
A living wall is a collection of plants grown up a vertical surface. A decorative design solution for smaller spaces, living walls are usually attached to a façade but can be set up indoors or outdoors. You can install the living wall yourself, call on the help of a professional or buy everything you need in kit form.
- Types of living walls
- Types of substrate
- Suitable plants
Living walls: the ultimate in plant decor
Creating a unique plant artwork
A living wall is a unique way to decorate a wall or partition wall in the home or garden. More dazzling than potted plants alone, the decorative effect of a living wall can range from a manicured tableau to an exuberant display.
A living wall can also be seen as a moving spectacle; these walls are not lifeless decorations and will continue to evolve over time. In fact, if looked after properly, a living wall will last a number of years.
Living walls are designed to reproduce what already exists in nature; just think about moist rocky walls that are eventually taken over by plants and moss!
Hydroponic living walls
This is the basic concept of a Living Wall System (LWS) or vertical garden as dreamed up by French botanist Patrick Blanc.
Layers of fabric, like Florafelt, are stapled onto PVC or moisture-treated wooden panels. The fabric panels are attached to the wall by a wooden frame or metal profiles.
The plant roots are inserted into felt pouches or between two layers of rot-proof horticultural felt which provides a substrate for the plants. The felt itself is soaked in a nutrient-rich solution made up of water and mineral salts. This solution falls into a tray at the base of the wall where it is directed back to the top of the living wall. The water is therefore closed in a hydroponic system.
Gabion living walls
These containers are based on the same concept as gabion baskets which are usually filled with stones to create retaining walls. In a living wall, the gabion basket features a 10 cm galvanised or stainless steel mesh and will measure about 40 x 40 cm or 50 x 50 cm (and around 10 to 20 cm in depth).
Arranged side by side and one on top of the other, these gabion baskets combine to form a wall of your required dimensions. They are fixed to a metal frame specially designed to withstand heavy loads. The watering and fertilising systems in these walls can be built-in and may even be automatic.
The gabion baskets are filled entirely or partially with a growing substrate such as peat moss or an ordinary growing medium like potting soil; in the latter case, you will have to use geotextile fabric to hold everything in place.
Modular living walls
An improved version of a gabion basket wall, modular walls are the latest in living wall systems. They are made up of moulded plastic modules with ready-made compartments for planting.
Easy to set up, the modules are juxtaposed like a set of planters. This type of system is usually equipped with a built-in fertilising and watering system.
Comparing different types of living wall
Gabion planter baskets
Easy to set up.
Least expensive option.
Thermal and acoustic insulation.
No daily upkeep.
Holds a lot of water.
Can be pre-planted.
Quick and easy to set up.
Root ball planting, quick.
No daily upkeep.
Roots protected from extreme temperatures.
Easy to change plants.
Can be pre-planted.
Soil nutrient monitoring required (EC and pH levels).
Doesn't hold a lot of water; potential low-water risks.
Lengthy to set up.
More expensive to install.
High weight per m2.
Not easy to plant.
High plant mortality rate due to a number of reasons:
•growing medium tends to get packed down over time;
•plants installed horizontally (not natural);
•peat is often used but holds a lot of water which can cause issues in winter.
Expensive initial purchase.
High weight per m2.
Not as attractive as other options while the plants are still growing in.
Growing media for living walls
The growing media used for green walls can be divided into two categories:
- media for hydroponic growing;
- media for conventional growing.
In a hydroponic system it is the fabric itself that serves as the growing medium.
The fabric used is traditionally a type of geotextile felt specially designed for the purpose. However, other types of non-organic media such as rock wool may be used.
In terms of the more traditional growing media, you'll find a mix of a few different materials including compost, peat, coco fibre, and so on. These substrates are widely available but do tend to pack down over time which will eventually create empty spots.
Sphagnum is special type of peat moss grown in Chile and often used for gabion living walls. Peat moss is able to absorb enormous amounts of water to provide a very humid environment which can be an advantage and a disadvantage. In fact, in the winter, these types of conditions can kill off your plants.
Pros and cons of living walls
Advantages of a living wall
Beyond their decorative effect, there are plenty of other reasons to create a living wall:
- These walls provide acoustic insulation meaning they will help to dampen sound both indoors and outdoors. Set up in a public space, a living wall will help to reduce ambient noise by several decibels.
- A living wall also provides thermal insulation. In the winter, the cold won't be able to penetrate the walls of your home as easily and the heat will be kept indoors. The reverse will happen in the summer when the plants will protect your home from the heat of the sun.
- A living wall also generates humidity which can help to cool down the air – a big bonus in hot weather!
- Livings walls have a positive impact on your mental health and overall well-bring. A bit like a living fresco, these walls are works of art in themselves which can provide a little escapism for the mind. A green wall may even help to harvest feelings of serenity and peace.
One of the main selling points of companies selling living wall equipment is that these walls improve air quality. This point makes reference to the de-polluting effect that plants have in indoor spaces.
Volatile Organic Compounds (VOCs) are commonly found in the home. However, it isn't the plants that will help to purify the air but rather the microorganisms in the growing medium. While plants are able to shift small amounts of VOCs, their purifying effect is quite minimal.
Downsides of a living walls
A living wall can only be installed under certain conditions. To set up a green wall you need:
- enough light: if your wall is indoors, it must be set up directly underneath a light source;
- some time to maintain the wall: a living wall does need a little time and attention, and the amount required will depend on the type of surface you choose;
- a water inlet and possibly drainage.
If you want to create your own living wall, you'll need to have some gardening knowledge; if you're not a seasoned gardener or a keen botanist, it's best to call in a professional. Specialist companies can be hired to help you set up your own living wall creation.
Living wall plants
All types of plants can be used to create a living wall from regional species to more exotic varieties. Moss, ferns, flowering plants, climbing plants, herbs, perennials... pretty much anything is possible.
However, you'll need to consider the needs of the plants you choose in terms of temperature and ambient humidity. It's also important to bear in mind that you cannot grow several species with very different care needs on the same living wall.
Living wall system kits
A range of kits, as described above, have hit the market in recent years. These include:
- felt systems with pockets and slots for fitting your plants;
- plastic, wood or metal modular kits designed to be attached to the wall; choose from a range of module sizes that you can assemble yourself into your own layout. Each module should be fitted with a substrate (peat moss, rock wool, potting soil, etc.) and the kit will come with openings for slotting in watering hoses and so on.
The watering system is very important and should be automated. The system will usually be made up of a water tray at the base of the wall, a pump to carry the water to the top of the wall and a soaker hose on the top of the wall or a dripper at the base of each plant.
It's also possible to find metal, wooden or plastic frames designed to line pots up next to each other. Some offer more features such as a drip irrigation system to feed each pot. The plants you grow will eventually hide the frame as they mature to create a fully green surface.
How to maintain a living wall
Living walls do not require a lot of maintenance. Every couple of weeks to a month, check the wall to ensure that the watering system is working correctly (or the lighting system if your wall is indoors). You will also have to add fertiliser and monitor the health of your plants.
In terms of hydroponics, living wall owners will want to check the following important indicators:
- the pH level of the water (i.e. the acidity of the water);
- the electrical conductivity (EC) of the soil which will give you an idea of the nutrients available.
You will have to take care of the plants themselves at least a couple of times a year. This involves trimming any overgrown plants, removing any dead leaves or stems and taking out wilting plants and replacing them with new ones. It's important to check that the water is running along the drippers smoothly and to clean out the water tray.
Preserved living walls
These days, you might come across so-called 'zero maintenance' living walls made up of moss, plants and flowers.
In fact, these walls have been preserved to keep the plants in a certain state; they have finished growing and won't need any water, but still retain their colour. The preservation process consists in replacing the sap of each plant with non-toxic glycerine. These systems last about a decade but they do require a fairly high humidity level (around 70%).
Guide written by:
John, Passionate gardener, Cambridge, 61 guides
When I was young, I was already working in the family garden. Perhaps that is where my interest in plants and gardening came from. So, it was logical for me to study both plant biology and agronomy. At the request of various publishers I have, over twenty-five years, written many books on the subject of plants and mushrooms (a subject that is close to my heart).They were mostly identification guides at first, but shortly after they were about gardening, thus renewing the first passion of my childhood. I have also regularly collaborated with several magazines specializing in the field of gardening or more generally in nature. There is no gardener without a garden, I have cultivated mine in a small corner of Cambridge for the last thirty years and this is where I put into practice the methods of cultivation that will I advise you in as well.