Recycling Your Wood Ash

April 8, 2015

One the downsides that come with the pleasure of burning your own fire is the daily clean out of the grate or stove – it’s a job we’ve happily forgone in favour of the quick flick of the central heating switch.

Wood Ash Versus Coal Ash.

But we who burn wood know better! Forget about the mountain of ash that comes with peat briquettes and the dirty soot and clinker of coal fires. Typically, only around 1% of a wood log ends up as ash. By comparison, anthracite coal has an ash content of around 15% of its weight. Also wood ash is clinker free – those occasional charcoal lumps that sometimes remain after burning wood are residual organic carbon and can be burned again. Also, for a wood fire to burn well it needs a decent bed of soft white ash for the embers to rest in and radiate heat but a coal fire quickly becomes choked by its own ash and must be well cleared before lighting.

What To Do With Your Wood Ash.

Wood ash has long been used as a valuable resource. Most commonly it’s used by gardeners: primarily as a soil improver and secondly for pest control.

Wood ash is a useful source of potassium phosphate (or potash). In places with high soil acidity, wood ash is used as a lime to reduce acidity. The gradual addition of wood ash will gently raise the pH level. Note, obviously plants that thrive in acidic conditions will not appreciate this! Also potatoes sometimes develop scab if treated with wood ash. But brassicas really benefit from wood ash as a treatment against club root. So if your soil is on the acidic side just rake in the ashes direct to the soil once they’ve cooled sufficiently.

Note also, because potash is highly soluble if it’s rained upon all the nutrients will leach out. It’s important to store it somewhere it can stay dry. Once wet, it becomes a slimy mess that’s impossible to handle and highly alkaline.

Wood ash can also be used as a physical barrier in pest control particularly against slugs and snails especially where the soil is damp and it rains a lot – pretty much everywhere in Ireland, so. Instead of raking in to the soil, form it into a ring around plants you wish to protect.

Historically, wood ash has been used in the making of soap and even now some people mix a little ash with water to use as a gentle abrasive to clean their stove door. Likewise, it can be used as a scouring agent to clean metals. Ashes from fires can be sprinkled on icy paths to make them easier to walk on and in pottery wood ash is used to create lovely dark green glaze!

If you have any uses for wood ash please do let us know in the comment box below.