Ashes in the Garden   

You may have heard that using wood ashes on your garden can help make the soil more fertile. Though  ashes do contain significant amounts of potash, they contain little phosphate and no nitrogen. Most Kansas soils are naturally high in potash and do not need more. Also, wood ashes will raise the pH of our soils, often a drawback in Kansas where soils tend toward high pH anyway. Therefore, wood ashes add little benefit, and may harm, many Kansas soils. In most cases it is best to get rid of them. (Ward Upham)