The science of soil

Healthy soil is teeming with life - Becky Searle delves below the surface to explore how this fascinating system works and how it can benefit our plants

- Becky Searle

Our gardens are home to one of the most biodiverse and mysterious ecosystems on the planet. Soil is the foundation of life on Earth, yet most of us consider it to be just sand, silt, clay and organic matter. We know that when our soil is healthy, our gardens thrive. But our attempts to create good soil can prove frustrating - often because few of us understand what healthy soil actually is. However, scientific knowledge has come on in leaps and bounds, so it's time for us gardeners to catch up. And in doing so, we'll unearth a world more fascinating and valuable than we could ever imagine.

Almost all life on Earth relies on the top 20cm of soil - what we know as topsoil. Far from an inert substance that helpfully holds up our plants, it's the most biodiverse ecosystem in the world. In fact, more than 50 per cent of species on the planet spend at least some of their life in soil. Many are so small that we just don't realise they're there.

Soil ecosytems 

The word ecosystem evokes images of lush forests, coral reefs and wild grasslands. We think of colourful and exotic places and turn a blind eye to those that don't fit our expectations. But the term ecosystem is very broad it's defined as a community of organisms interacting with one another in their environment. So they can be as varied as the creatures that live in them.