Professional coir solutions for cannabis growers. Growers looking for a free draining coir substrate for precision growing look no further than high quality coir for marijuana sold by us. We Riococo / Ceyhinz Link, Inc. are the leader in producing 100% organic coco coir medium to the hydroponics. When you choose us, you choose the best. Our custom cannabis growing medium mix gives bigger, faster and stronger healthy roots from cloning to vegging to flower-cycle.