Black Gold 8 Qt. Perlite. It is used as a soil amendment and to improve aeration and drainage. Its moisture and nutrient retention capabilities and lightweight characteristics make it an excellent sterile medium for starting seeds and rooting cuttings. It does not degrade over time, which makes it a long term solution to many gardening problems. It can be used to start seeds, root cuttings, or store bulbs and for making hypertufa planters.