"Stuart Noble" wrote in message
...
The recent Joanna Lumley programme about Japan visited a volcanic island in the extreme
south where the world's largest radishes are grown. I can't figure out why a pumice rich
soil would be any different to vermiculite or perlite, all 3 having the same properties
of air and moisture entrainment. No mention of nutrients, but there must be some in
volcanic soil? Puzzled...again.

Volcanic soil is particularly rich in potassium and is of great benefit to potatoes
so would guess that radishes would also benefit.

Phil