"songbird" wrote in message
...
W wrote:
What is the most economical source for a large bag of small red lava
rock,
to be used as a replacement for pumice in a succulent soil mixture? I
also
want to use the red lava rock as a mulch.

the stuff floats away easily, so not the
best mulch if you get heavy rains, winds or
floods.

Are you confusing lava rock with perlite? Perlite definitely floats.
Volcanic aggregates (i.e., either white pumice or red lava rock) sink in
water.

I did a quick test with 10 smallish red lava rocks in a bucket of water, and
they all 10 sank.

--
W