|A bucket of wood ash|
|Spreading wood ash on the garden - I just hose it into the soil|
|The clever ash tray on our wood stove|
1) make sure it is completely cold. I spread ash directly from the woodstove onto dry mulch once and had to very quickly stamp out a fire, even though it didn't seem hot at the time, it was still very hot inside. Its also best to use a metal bucket to store ashes, plenty of fires start from plastic buckets of ash melting through, and keep the bucket on concrete or dirt rather than wood or plastic.
2) test your soil pH as all those mineral oxides form hydroxides with water, which will increase soil pH. Soil pH tends to decrease as calcium ions are leached, so usually it is safe to add wood ash to maintain calcium ions and a neutral pH (7), but if you have naturally high pH soil, then don't add wood ash.
Speaking of hydroxides, the other use for wood ash is to soak it in water to make lye for soap making. This is the traditional method, and much more difficult that using purified sodium hydroxide (caustic soda) like we can do today. I'm tempted to give it a go one day though.
How do you use your wood ash?