Good morning all. My brother Paul, CEO of Tree Awareness, normally writes the blog. I asked if I may add my two cents. I am by no means an expert, but I am a hobbyist gardener. My name is Donna and I will be posting to the blog from time to time. Please feel free to ask any questions you may have. We may not have all the answers, but will do our best to find it for you.
Since the frost has begun, I have been lighting a fire almost nightly in my outdoor fireplace. We are saving the ashes for the garden!
Since wood ash is derived from plant material, it contains most of the 13 essential nutrients the soil must have for good plant growth and health.
When wood burns, nitrogen and sulfur are lost as gases, and calcium, potassium, magnesium and trace element compounds remain. The remaining carbonates and oxides are valuable liming agents, raising pH, thus neutralizing acid soils. Soils that have acid and are low in potassium benefit from wood ash. However, acid-loving plants such as blueberries, cranberries, rhododendrons and azaleas would not do well at all with an application of wood ash.
The chemical makeup varies with the type of wood burned. Hardwoods produce three times as much ash per cord as do softwoods.
Wood ash can be used to repel insects, slugs and snails because it draws water out of these invertebrates. Sprinkle ash around the base of your plants to discourage surface-feeding insects. Once ash gets wet, it loses its deterring properties. Too much ash can increase pH or accumulate high levels of salts that can be harmful to some plants, so use ashes carefully.
You should store your wood ash in a metal container with a lid to prevent any fires from live coals.
Never leave wood ash in lumps or piles. Concentrated piles of wood ash causes excessive salt build-up in the soil through leaching and can create a harmful environment for plants. Use in moderation.