(originally published August 2008, updated February 2010)
Depending on where you live, a wood heater can be a *relatively* earth friendly
option for heating (see my article on wood
heaters and buying
firewood) and quite economical; particularly if you're fortunate enough to
have easy access to a supply of wood.
The ashes left behind from a wood fire are also a valuable and versatile
by-product - don't just throw them away indiscriminately; here's some great uses
for your ash! Per usual, exercise appropriate caution, spot test etc. etc. etc.
:).
Fire helper
Lumps of charcoal shouldn't be removed from your fireplace if possible, just
the ash - the charcoal will help kick along your next fire and get it cranking
out decent heat far faster than if a fire is just started with wood alone. You
could also save it and use it for summer barbecues, rather than using some of
the commercial products that sometimes have toxic chemicals added (see my
related article on greener
charcoal).
Filter
Left over charcoal (the black chunks, not the grey/white ash) can be pounded
with a hammer and then ground into to a fine powder with a mortar and pestle or
blender. This can then be used as a filter medium. Note that it's not quite the
same/effective as activated charcoal that you buy, so don't rely on it for
filtering drinking water.
Pest deterrent
Sprinkle the ash around the border of garden beds to repel
snails and slugs. This will need to be applied after rain.
Ice
Wood ash can be used as an anti/de-icing
agent - a little more environmentally friendly than salt or other chemicals
used these days
Making lye
Lye is used in the production of soap and biodiesel - white ash produced by
burning hardwood is best for this purpose. Learn
how to make Lye water here.
Compost
Add a dusting of wood ash to each layer of your
compost heap as you're building it up.
Fertilizer
Ash contains potash (potassium carbonate), phosphate, iron, manganese, boron,
copper and zinc and can be quite beneficial as a natural
fertilizer... sometimes. Wood ash increases the pH or alkalinity of soil, so
use sparingly. I made the mistake of applying a stack of it in an area full of
limestone - and guess what else is in ash - lime (calcium oxide). It wasn't the
smartest move and I don't think anything will be growing there for a while.
Black charcoal is a little different in that it has a much higher ratio of
carbon - so this can be used more liberally.
Dehumidifying
Lumps of charcoal placed in a can punched with holes can help reduce moisture
in areas such as closets, basements, under sinks etc.
Cleaning
Dip a damp rag into ash and use to clean silverware, brass and glass. Ash
added to a scourer can also give your scouring a bit more oomph.
If you do intend on using wood ash and carbon, be sure not to throw icky bits
such as plastics, cigarette butts and such (which you shouldn't do anyway) into
your wood heater or fireplace as it can contaminate it. Ash should be stored in
a metal container with a lid. Of course, you should also wait for it to cool
before using for any of the above purposes :)
Know of any other uses for wood ashes? Please share your ideas below.
