The HDI Root Riotâ„¢ Tray contains plant starter cubes for cuttings and seeds for soil or hydroponics. Derived from naturally composted fine milled sphagnum peat moss and are fully biodegradable. Root Riotâ„¢ will give you faster, more vigorous rooting. Perfect air/water capacity for healthy roots. New plants transfer easily into soil or any other media.