The soil pH is an important factor in determining plant growth.
The soil may be neutral, acidic or alkaline.
The pH scale is a scale of value for the degree of acidity or alkalinity of a soil.
The soils below 7 pH are regarded as being acid, those above 7 as alkaline.
A pH value of 7 indicates a neutral soil.
An ideal garden soil PH reading is 6.5.
Below 6 on the scale, the extreme acidity of the soil makes it suitable only for acid-loving plants such as heathers and rhododendrons.
A reading above 8 means that the soil is so alkaline that it will support few plants, due to essential foods being ‘locked up’ in the soil.
Certain plants such as carnations, sweet peas and onions prefer alkaline conditions. The level of acidity or alkalinity can be controlled by adding lime, peat and various chemicals such as sulphate of ammonia to the soil.
Lime helps to reduce the acid level of a peaty or sandy soil while peat and sulphur make a chalky soil less alkaline.
