Diamond Black by General Hydroponics is a superior fertilizer that is derived from naturally occurring carbon. This carbon is drawn from prehistoric peat bogs and is specifically called Leonardite. Leonardite is the main substance in Diamond Black and provides your plant soil with microbial activity and increased micronutrients. Diamond Black can be used on a variety of plant types and during all growing phases. Simply add to garden soil or potting mixes and watch your plants say healthy and happy! Quantity: 2.5 Gallon.