DIGGING DEEPER - GARDENING IN-DEPTH
For many years, we gardeners have thought of soil as an inert substance composed of only a few inorganic materials mixed with some dead things and some earthworms. We have agonised over which type of subsoil and bedrock we have. We've attempted to ‘fix’ clay soils by adding grit and sand, and we've been frustrated if our soil just isn't right. In recent years, our understanding of soil has begun to shift towards a more biological viewpoint, accepting that soil is one of the most biodiverse ecosystems on Earth. It is the availability of micro-organisms and fungi in the soil that determines the availability of nutrients for our plants. The bacteria and fungi in the soil act like an external gut for our plants.
SOIL PH
While the inorganic components of soil are important and can cause us some challenges, most can bealkaline. For your reference, battery acid sits somewhere near pH 0 (most acidic), and drain cleaner sits around pH 14 (most alkaline) – neither of which you want on your skin or anywhere near your kids! These extremes are very reactive, depending on what they are mixed with, but the higher or lower you go on the scale, the more reactive things become. Right in the middle, at around pH 6.5 to 7, is neutral. Pure water is neutral. The pH scale is logarithmic, meaning that a pH of 6 is 10 times more acidic than a pH of 7, and a pH of 5 is 100 times more acidic than a pH of 7. Most plants are happy in neutral soils, with the exception of certain plants that thrive in ericaceous soils – or soils that are slightly acidic. These include blueberries, azaleas, rhododendrons and acers. While they will grow in alkaline soils, they won't perform to their best. Blueberries in alkaline soils will struggle to produce fruits, for example.
