The coco bricks are ideal for indoor or outdoor gardening, CocoTek is pH balanced, and contains the lowest known sodium content for coir fiber. It increases water holding capacity and nutrient retention, expanding to 5 times its condensed brick size (1 brick expands to 3-1/2 gallons). CocoTek can be mixed with any other growing media (Perlite, Grow Rocks, soil, etc.) to make the desired final mixture.