PH

Global variation in soil pH. Red = acidic soil. Yellow = neutral soil. Blue = alkaline soil. Black = no data.

Soil pH is a measure of the soil acidity or soil alkalinity. An acid solution has a pH value less than 7. While a basic solution always has a pH larger than 7.

Soil pH is an important consideration for farmers and gardeners for several reasons:

• Many plants and soil life forms have a preference for either alkaline or acidic conditions, affecting the choice of crop or plant that can be grown without intervention to adjust the pH.
• Diseases affecting plants also tend to thrive in soil with a particular pH range
• The pH can affect the availability of nutrients in the soil.

The majority of food crops prefer a neutral or slightly acidic soil (pH 7). Some plants, however, prefer more acidic (e.g., potatoes, strawberries) or alkaline (e.g., brassicas) conditions.