Q: About vermiculite.
Vermiculite (background)
A: Vermiculite is a relative of mica. Like that mineral, vermiculite
consists of many little sheets pressed against each other, like the bellows of
an accordian. Because of special processing for horticultural uses, it is
water-absorbent and so is similar to peat. However, in time it tends to break down
into a kind of nasty muck so is often not a popular alternative.
It is particularly popular with aficionados of Mexican Pinguicula, who use it in various fractions with
perlite and other additives. (Do not email me for details--I'm no Ping expert.)
Wash vermiculite before using it.
Page citations: Rice, B.A. 2006a; personal observation.