Heres a wonderful potting medium for orchids thats made entirely from natural coconut husks. It holds more water, air and nutrients than bark chips and does not dry out as quickly. Coco husks contain five times more lignin than bark so it doesnt break down as quickly. Compressed bricks measure 2 x 4 x 8. Soak in water for 15 minutes before using. Each brick yields 1 gallon of potting material.