Way to grow processional coco chipped blocks (12-25mm) are a fast draining formula that is idea for recirculating systems or as a run to waste winter mix. 12-25mm Coco Chips are RHP approved for horticulture and are Australia’s premium coco/perlite blended substrate (RHP 088BK09. ISO 9001:2008). 12- 25mm Coco Chips are buffered with calcium & magnesium and also contains trichoderma for fast root stimulation and optimum plant health.