What is acid soil and can it be fixed?

The answer

Acid soil has a low pH, where 7 is neutral and lower numbers are more acidic. Low pH can make some metals more soluble and reduce the availability of nutrients, so crops grow patchy and stunted. It is commonly corrected by adding ground limestone or a similar liming material in an amount guided by a soil test; over-liming can cause its own problems. Reducing acidifying inputs and returning organic matter help prevent the problem returning.