CocoTek Compressed bricks are composed of low sodium coconut coir and chips. Each brick will expand to about 2.5 gallons when re-hydrated with water. CocoTek Organic Growing Media is ready to use in a mixed brick (25% chips and 70% coir) or make your own blend by combining the Chip and Coir bricks. The Coir brick provides excellent water retention and the Chip brick improves aeration. A custom mixture of the two creates an ideal growing medium for a specific growing environment.