DaisyI said:I do all the time. Its really interesting stuff - you will have to do some experimenting to see how it works for you. Its great for holding air spaces open and doesn't decompose so works well in epiphytic orchid mix. But, I have also used it in cactus mix, terrestrial orchid mix and in my hoyas, so, for those plants, I am relying on it to keep the soil mix dry and porous.
I have also used it straigth for some orchids (don't tell BigBill) and as a medium for water cress in my pond. Its biggest detractant is it floats.