Using COCO COIR is rapidly growing in popularity worldwide and it has become the most widely used medium in Commercial Hydroponic Cultivation. It is light and holds large amounts of water and air. It comes in various grades which drain at different rates, suiting different hydroponic systems. It is inexpensive, reusable and completely environmentally friendly, emanating from a sustainable resource – the husk of the coconut. It is so popular that growing with COCO has been given its own name: Cocoponics.