Wood Ashes as Soil Amendment

Wood ashes are often used as a soil amendment. They contain potash (potassium), phosphate, boron, and other elements. Wood ashes can be used to raise soil pH; use twice as much wood ash as limestone for the same effect as lime. Ashes should not come into contact with germinating seedlings or plant roots as they may cause root damage. Spread a thin layer during the winter and incorporate into the soil in the spring. Check pH yearly if you use wood ashes. Never use coal ashes or large amounts of wood ash (no more than 20 pounds per 1,000 square feet), as toxicity problems may occur.