Function

• Wood ash, as a plant byproduct, contains many minerals that are essential to plant growth. It's high in lime, which raises the pH of soil, and is sometimes used to enrich soils that are low in potassium.
  
  

Prevention & Solution

• If you aren't sure what type of soil you have, take a sample for testing. Alkaline soils should never be amended with wood ash. Choose acidic organic matter instead, such as compost and peat moss, to lower the pH and create a hospitable growing environment.
  
  

Warning

• Do not use wood ash in conjunction with nitrogen fertilizers, including ammonium sulfate, urea and ammonium nitrate. These compounds form a dangerous ammonia gas when they come into contact with high-pH substances such as wood ash.