Coco Coir Brick - 2.8 lbs in a 5 Gallon Grow Bag - OMRI Listed for Organic growing medium 1 block expands to fill the 5 Gallon of grow bag after hydration with water. Organics Material Review Institute(OMRI) Listed product High-grade coconut coir with low EC (Less than .8) and optimum pH levels of around 5.8 to 6.8, Prewashed to remove Salt Perfect for cuttings, seeds, plants, vegetables, hydroponics, mushrooms and worm farms Professional grade as used by Hydroponic and other large scale growers around the world