Wood ash can pile up during a cold winter and it would be nice to have a practical use for it. But gardeners have been given mixed signals about using wood ash on their garden soil. Is it safe to use wood ash in the garden? Is wood ash good for garden soil? The answer is both yes and no. Ashes from fireplaces and wood burning stoves are a good source of potassium and a lesser source of phosphorus and some micro-nutrients, depending on the type of wood burned. So if your soil has a potassium deficiency, wood ashes can be a good amendment. Continue reading the expert opinion in the source.