I've been playing with adding Kanuma soil to my crypt soil mix as an experiment.
Kanuma is a soil mined from the region of Kanuma in Japan. Its an acidic soil, folks usually
grow acid loving plants in it - like azeleas, gardenias and some bonsais.
Anyway, I got some from a bonsai supply store to try out as part of my crypt mix. I tried 100% kanuma in several pots, as well as 95/5 Kanuma/Leaf compost. The three different cordata
varieties I'm growing in it are showing very good growth. I dug up one of the plants to see the root health, and
that looks pretty good too. One of my C. longicaudas I was growing in near 100% Kanuma was also showing really good growth - until I ripped it out to trade
. Anyway, if you want to try it, I'd reccomend it - atleast for
experimentation purposes. I havent been using it long enough to say its better than anything else, but the results
are looking decent.