Walnut is toxic. It is not good for the micro organisms in the soil, for the
worms, for horses, for anything. I agree, don't use walnut or redwood.
Redwood has a chemical in it that retards growth for stuff that is not
redwood.
max

Duane Bozarth wrote in
:

Also note the caveat on oak in particular as high tannic acid
content...walnut is to be avoided entirely.

Unless you WANT to keep the weeds down in certain areas...

Patriarch