I found four lava or red clay media sitting in my growing area. From top left clockwise: lava sand, red lava, unlabelled, burnt earth (fire kilned red clay)
Considering input from jimscott and kulamauiman, I potted three simlar size D. dilatato-petiolaris plants in three different media (lava sand, red lava and burnt earth - all individually mixed with peat and sand).
Considering input from jimscott and kulamauiman, I potted three simlar size D. dilatato-petiolaris plants in three different media (lava sand, red lava and burnt earth - all individually mixed with peat and sand).