| Hi Sharyn,
Lava rock does not decay or break down, therefore it can be reused as a
potting medium provided it is sterilized. It is well aerated in the pot and retains
water pretty well although not a much as fir bark. There is no nutrients in
the rock so a 20-20-20 fertilizer should be used as a supplement. Another
advantage of its use is that it adds stability to the pot. One disadvantage is
it does tend to accumulate salts, so if your water contains dissolved minerals
in large amounts, there could be a buildup of salts. One of the local growers
uses it with his Paph mix with good success. |