Originally Posted by Snarkie

Wood ash is an awesome amendment to your garden soil, but there are a few things to know before using it. As has been stated, it raises the pH significantly, so unless you are growing 9 volt batteries, you will need to tame it down. I mix sulfur in with it, which helps to counteract the alkalinity of the potash. It also adds the element to your garden which is needed by most plants. Except onions. They have enough already! Also, if a little charcoal happens to mix in with the ashes, it will help after it's activated itself.

Keep in mind that wood ash is only good until the first time it rains, at which point all of the nutrients will leach into the soil and be lost. If you are going to add ashes to your garden, use ashes from the fireplace, wood stove or a fresh burn.