My grandparents used to spread the ash from the fireplace on the vegetable plot. This was in reasonably large quantities (I mean, not just a thin trail of ash to deter slugs), and was done to "add" to the soil. Visually, it was an eyesore, but they didn't worry about that.
I am sure I've read elsewhere that this practice is without value, and in fact I dump our fireplace ash out for the bin men. But every time I do it I wonder whether I should be using it in the garden. And it's free, and I have to cart it straight past the veg anyway, to get to the dustbins.
So, is it useful to add ashes as a kind of fertilizer?
Edit We are mostly burning firewood, sometimes with a small amount of Taybrite