Dry Premium Organic Humic Acid Perfect for soil and other soilless growing media. A pure, mined material that meets all organic standards for crop production, Diamond Black consists of the richest agronomically effective and organically certified plant-active humates. It is commonly understood that humates regulate the flow and enhance the transport of vegetative nutrients, and that they work best when applied continuously during the growing season. Diamond Black is significant because it is the only granular leonardite that has been proven soluble during a single season. Once it is blended with rooting media, Diamond Black will slowly break down and add humates to your plant's root environment.