St George BLACK LIME™. A Rock Dust of Great Fortitude. All purpose "grits-to-dust" for adding minerals to growing media and sweetening soils. Regulates pH of growing media naturally. Great source of soluble calcium. Builds mineral structure and adds carbon. Manages phosphorus leaching. An unoxidized clay-like mineral complex of high nutritive content including Nitrogen, Phosphorus, Potassium, Silicon, Calcium, Magnesium, Iron, Sulphur and significant traces including Vanadium, Zinc, Cobalt, Chromium, Copper, Molybdenum and Boron. Includes nearly 5% total carbon, 1% organic carbon and .1% total nitrogen. Suggested application rates: Broadcast to ground at between 5-25 lbs./100 square feet, fully incorporate. This material has alkaline earth elements which will tend to buffer acidic soils as the material weathers, can be a 45% substitute for lime. Manages Phosphorus run-off by capturing excessive solution reactive phosphorus. A unique and valuable proposition. See the John Kohler Growing Your Greens video for a look at the quarry and to learn more about this great resource!