"david taylor" wrote in message
...
Many sources of coal ash are toxic to plants, I would not use it. The old
NCB did a lot of work identifying the toxic trace elements in some coal
ashes and on the selection breeding of strains of resitant plants to
colonise old pit heaps. Boron and I think copper at the 10s of ppm level
were the principal offenders. I occasionally pass the pit heap at Cefn
Mawr
just south of Wrexham and it still has only a few isolated plants growing
on
it after at least 30 years.
I don't know what particular benefit a non toxic source of coal ash would
bring.

"Cumberpach" wrote in message
...
I remember an earlier thread which indicated Wood ash was ok for soil,
although there is a tendancy towards alcalinity.
My adj allotmenteer has started to put soft-coal ash from his open
fire on the soil. Is this ok please ?

Since posting this article, I tested the soil and found it to be on the
alkaline side of neutral. As wood ash makes the soil more alkaline my
neighbour has agreed not to add wood or coal ash.
My father was from the Rhondda and I note that the Forrestry Commission has
made some progress with the Tips (post Aberfan). I suppose a lot depends on
the soil content. They would also use coal-fired steam engines for the lifts
and I suppose the ash would end up on the tips.

Pete