Amazingly, for any of us that live in Europe, it seems like all commercial plants are potted up in a mix of biochar and sand. Nearly all char in fact. Seems to be working but we’re not quite sure of the process used to transform the readily available rice husks to biochar. But we’re onto it, we’ll get an answer!
(Actually, we’re not even sure it’s biochar. May be just rice husk ashes? Remains to be seen)
Either way, I’m pretty sure we can improve the mix by incorporating EM snd bokashi. We made a friend in one of the tiny garden shops that line the park pathways and I’m sure he will help us in due course. He’s on our wavelenth: an organic guy!