pH ..What’s that got to do with it ?

Firstly, what is pH, what does it mean to us and why does it matter?


pH in simple terms is a measurement of the acidity/alkalinity of the soil. These two things are fundamentally opposite to each other, and whether a soil is more acid than alkaline can be demonstrated be determining its pH.

A pH value is given by giving it a numerical value between 0(zero) and 14. The number 7 is considered to be neutral – neither one thing nor the other. The lower the number below 7, the more acid the soil is, and the higher the number above 7, the more alkaline the soil is.

In general terms, the pH levels in an average garden’s soil tend not to be lower than 5, nor higher than 9, although there will always be exceptions.

So why on earth does it matter what the pH value is? It is simply because of what certain types of plants will or will not tolerate. It’s a bit like very dry or very wet soils, or very hot or cold situations. Some plants can cope and some cannot.

So it is important that we take note of soil pH so that we can make a well informed choice where selection of species is concerned.

There is no substitute for learning about popular plants and what their specific requirements are.

In horticulture, one of our primary functions is to find the right plant for the right situation. In order for us to do that, there are certain basic things that we need to guide our choice. Soil pH is just one of them.

Chalky or alkaline soils have a high pH

Very light acid soils have a low pH