" Harris Coconut Coir Pith Compressed Coconut Fiber Expandable Substrate. For Healthy Roots Use as an additive to soil and potting mixes for even distribution of nutrients Moisture Retention Can absorb up to 10x its weight in water, making adequate root hydration easier than ever Improves Aeration Adding coco coir fiber to soil allows for coir's fluffy texture to create air pockets, making soil spongy and loose Indoor and Outdoor Use From indoor potted plants to an outdoor garden, coir is extremely versatile Natural and Biodegradable Great for hydroponic and organic growers Coir, or coconut fiber, is extracted from the outer husk of coconut. Use as an additive to your soil or potting mixes to distribute nutrients uniformly and allow the roots of the plant to grow thick and healthy. The pack includes 4 bricks, each measuring 8" x 4" x 2" and expanding to approximately 9 qts once hydrated (at least 8x its original size!). Simply soak brick in water and watch it absorb and expand. Coco Coir helps soil retain moisture, improves aeration, is versatile for indoor outdoor use. Great for hydroponic and organic growers. Directions: When ready to use, soak one coir brick in warm water allowing penetration through the fibers. As water is added, the coir brick will start to absorb and expand. Keep in mind this will expand to at least 8 times its size. Drain excess water and break apart the expanded fibers with your hands or trowel to use desired amount.