A friend came across some cheap cinder block and wanted to make a raised bed,
but had read they contain fly ash.
Does anyone have recommendations/experience regarding this?
Call the concrete products companies that produce these things and they
will tell you what goes into them. I have heard that fly ash has been
used for years. So, what toxic residues are in it? Possibilities:
mercury
cadmium
cobalt
lead
?
?
?