Coconut coir is a 100% renewable resource that is rapidly replacing peat moss as the ideal, soil-less planting medium. It's physical structure - excellant moisture retention properties and superior drainage - make it one of the best bedding materials for your worm bin. The compacted, dry bricks need only to be soaked in warm water to turn them into fluffy, porous, mulch-like material that worms love to live in. Features: * expands to 8 to 10 times it's weight * Each brick is individually wrapped * ph between 5.2 - 6.8