Soil pH, soil acidity, and their effects on plants The pH scale, ranging from 0 to 14, is used to indicate acidity and alkalinity. pH is a measure of the concentration of hydrogen ions (symbol = H) in the water contained in the soil. A pH of 7.0 is neutral, values below 7 are acidic, and those above 7 are alkaline (basic). The lower the pH, the more acid the soil. Each unit pH drop indicates te...
