For those who burn wood in a fireplace or a stove there comes a time when you must get rid of the residual that is left over. This is commonly known as wood ash. The good news is that the wood ash can be added to the garden as a soil amendment. The ash is full of beneficial nutrients that will help improve your soil. When wood burns nitrogen and sulfur are given up as gases into the air but potassium ,calcium, and trace elements remain. The addition of wood ash helps to raise the ph of the soil this is good for acid soils and helps with soil which is low in potassium. The down side is that wood ash should not be used around plants that are acid loving plants such as cranberries, rhododendrons, and azaleas.
Wood ash particles are very small so they will breakdown quickly and react with the soil. Because there are not large amounts of nutrients added by the ash the main benefit is that of a liming type of agent. It helps with raising the ph of acid soil. The amount that can be safely added each year is around 20 lb per 1000 square feet about a 5 gallon pail full this is the equivalent of 6 lbs of ground lime. I
There are other uses for wood ash in the garden as well it is not just a soil amendment. When you are building your compost piles it is a good idea to sprinkle in a couple of shovel fulls on each layer. The wood ash will help to keep a more neutral ph and the microorganisms work best in these condition especially if your pile contains a lot of acidic leaves such as pine needles or oak.
Another use is to help repel garden pest such as snails and slugs. The ash will draw the moisture out of these pest so lay a band around the base of your plants. The ash will loose it’s benefit though once it gets wet and too much will leach salts into the soil so use sparingly.
There are a few precautions you should take when working with the wood ash .You should protect yourself as you would if you were handling strong alkaline material. Wear eye protection, gloves and a dust mask.
Do not use ash from burning trash, cardboard, coal or pressure-treated, painted or stained wood. These all contain chemicals that could be harmful. Do not mix with fertilizer as high alkaline substances can cause nitrogen to be released as a gas and neutralizes them.