Coir is the 100% organic, natural fiber derived from the husk of the coconut. Like tiny micro-sponges, it expands to hold up to 5 times its weight in water and has high air porosity for excellent aeration. Each block expands creating 2 to 2 1/2 gallons of wetted coir. Use for growing roses in pots or add as a top dressing to your rose bed once a year. Due to its high water retention properties, less watering is required. Its balanced pH and organic nature also makes it a good additive for mixing with other raw materials in the growing medium. Lightweight and easy to use.