WORM CASTING MAGIC: I add one to two inches of old leaves to the bottom of each potted plant here at Bamboo Grove. I then toss over that an inch or two of composted millipede castings, then I add soil. As the leaves rot in the bottom of the pot earthworms are fed and grow large. Bamboo leaves take longer to decompose but they still work well in the end and the worms seem to relish live oak leaves the most. That's why you see worm castinngs on top of the soil in many of our pots. I didn't sprinkle worm castings into the pot, the worms excrete them at night on the top of the soil as they move around. Living soil trumps sterilized potting soil mixes for sure. GO WORM CASTINGS!