General Hydroponics Diamond Black is derived from 100% pure Leonardite, a naturally occurring form of carbon drawn from prehistoric peat bogs. Diamond Black contains an exceptionally high percentage of plant-active humates. These organic compounds improve nutrient absorption, stimulate microbial activity, promote soil structure, increase nutrient retention and reduce water usage in the landscape. Use with all kinds of plants during all phases of growth. Additionally, Diamond Black can also be utilized as an additive for making compost. Use Diamond black with any garden soil, potting mix, or other soil-based media.