#1. Yes, wood ashes are good...
Just remember a weee~bit of ashes' goes along way... *not the ole adage, that a little bit is good, so more is better.. nope.. has a negative effect, if you're attempting to use right away*
#2. ONLY USE WOOD ASHES', neverrrrrrrrrrr COAL,
*coal is TOXIC for
plants*......
and only use wood products, no Plastic's or such.. those are also toxic.
#3. If you can, use them the season BEFORE you're intending to use the garden, ie; put on in the fall time, just after clean up...
Then it has time to render in, be useful for helping the soils' nutrients and breaking down the soil..
Also, ashes are great on hill top driveways, in the wintertime.... gives a little bit of grip~age to the tires going up or down the hill and is an okay thing to use as far as an organic product that dissipates thru winter and it's water.