We sometimes describe our gardens as ‘outside rooms’ – but a garden is so much more. The main difference between interiors and exteriors is living material. It is our proximity to plants that has the biggest impact on our mental wellbeing, but for that to be possible, plants need soil. Soil, therefore, is what makes a garden.
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Soil is something we all have experience of. It’s beneath our feet; we see it everywhere. But when we’re making changes to our gardens, it’s easy to take soil for granted. After all, soil will always be there, right? All gardens have ‘soil’ and where they don’t, we can simply add new ‘soil’.
More than half of all species are found in soil; it is the most diverse habitat on this beautiful Earth
If you’re gardening on a new build, you may be wondering why you’re struggling to establish new plants, and where and what your soil is. In my own garden, I have mainly sandy clay. That differs to my first garden that was loamy clay and which performed quite differently. My sandy clay develops an impenetrable cap after heavy rainfall that even my border terriers’ small feet manage to compact.
It’s an old Victorian house and the soils in some areas also contain the remains of many buildings, so I have areas of bone-dry rubble and gravels, with a thin layer of who knows what. In both areas, planting is the answer.
The roots keep the soils more open and will in time compost down and enrich the ground. Sounds easy, but it’s back-breaking work, so each year I tackle a new area. Timing is critical, and I have a small window at the end of winter when the soils dry out enough to be not too wet and heavy, and a spade smears the soil, and a week or so later, when my fork bounces off the surface as the soil dries. Each spring, I look around and put ‘easily workable soil’ top of the wish list for my next house.
Gardeners talk a lot about soil – meaning simply the top layer of earth that plants grow in. But in winter, or after heavy rainfall, even I start to fall out of love and my once-precious ‘soil’ changes quickly into ‘dirt’, traipsed into the house on muddy boots or paws.
The words and phrases we unconsciously choose not only reflect our understanding, but also affect our behaviour. ‘Dirt’ is a problem. Soil, however, is simply marvellous. It’s an excellent store of carbon acting like a sponge, and if the soil surface is not compacted, rainwater will percolate in.
Soils are also a key part of the solution needed to manage our changing rainfall patterns, which are increasingly feast or famine
More than half of all species on this planet are found in soil; it is the single most diverse habitat on this beautiful Earth. An inch of topsoil can take several hundred years to develop. Pioneer plant species die and decompose, creating pockets of soil in which a succession of more complex plants and fungi establish. These soils are the basis for the transition from a barren, lifeless habitat to a balanced ecosystem.
In the UK, we are fortunate that our soils have been mapped, and they make for interesting reading. In England alone, we have peat bogs, shallow lime-rich soils over chalk, free-draining acid sandy soils and acid, loamy clays, lime-rich loams and everything in between.
We need to recognise the value of soils, cherish and protect them
This soil diversity drives above-ground biodiversity. Thriving native flora is closely linked to soils and we see this in regional variation in our woodlands, hedgerows and meadows. This, in turn, is linked to diversity of insect populations, birds and other wildlife, and this above-and-below-ground diversity is key to climate resilience.
Soils are also a key part of the solution needed to manage our changing rainfall patterns, which are increasingly feast or famine. More than half of the green space in urban areas is covered by gardens, so it’s easy to see how important a role gardens might play in slowing down the passage of rainwater into our drainage systems, with the potential for easing the impact of flooding down the line at times of heavy rainfall.
If we can keep some of this moisture in our soils, it will also help in times of drought, narrowing the time period when our plants might be under stress.
We need to recognise the value of soils, cherish and protect them, and celebrate the diversity of plants they allow us to have in our gardens. So on those days where all you see is mud or dust, and you dream of having that famed fantasy moisture-retentive, well-drained soil in your garden, try to remember: it’s not just dirt.
Helen Elks-Smith is a garden designer. To find out more about soil mapping, visit landis.org.uk/soilscapes