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Living Wall Technical

How to choose a natural soil green wall system

Do all living walls use soil?

As plants naturally grow in soil, you would be forgiven for thinking that all living walls use soil.  However there are hydroponic systems which keep the plants alive with water and feed and the plants are in a man-made substrate.

Why would you chose a system with natural soil?

Your initial logic that made you assume plants would be growing in natural soil is sound however.  Consider how a garden changes with the seasons, in winter when the ground freezes, the plants go into dormancy, in spring when the ground is damp and the weather is mild, the plants grow and burst into life and in summer when the sun bakes the ground hard, the soil contracts with the plants roots, protecting them.  You might see the grass in parks turn yellow in the hot summer months, this does not mean the grass is dead.  It is the plants natural response to the season.  When it rains, the grass quickly greens up again – its nature way.

The same principle applies in vertical planting.  If something goes wrong with the irrigation system, a system that uses natural soil can last for weeks.  The plants might suffer, but will not die as the soil protects the root system.  In a hydronic system a failure of the irrigation means cutting off the plants lifeline of feed, when you cut the supply it means devastation for all of the plants in the green wall in a matter of days. Nature’s way proves to be the most resilient.

Vertical Pocket Planter Systems

There is another trap to be aware of however.  Not all natural soil living wall systems are the same however.  Some systems fall under a category known as ‘pocket’ living wall systems. These systems are either made from woven fabric with pockets for each plant or with plastic pots with one or more plant per pot. These systems can look impressive with a full coverage when initially planted. In the long term however the constrained rooting space causes plants to fail frequently. This leads to higher maintenance costs with plant replacements or an unsightly failing wall.

Some pocket systems are very basic and lack automatic irrigation systems, while others do include irrigation. Overall these systems offer a false economy with low initial costs but a long term struggle to keep the plants alive.

To learn more, consider an educational CPD for your architects practice, or contact us about your project to find out how our system can work for you.