Roots Organics HPK liquid bloom booster features a combination of seabird guano, an unparalleled source of available natural phosphorus, phosphate rock, and langbeinite, a natural source of potassium that is carefully mined from ancient sea beds in the deserts of the American Southwest. Aurora Innovations has taken generations of gardening experience and distilled it into a distinctive, easy-to-use formula for the home and professional gardener. Roots Organics HPK is minimally processed to preserve all the benefits and amazing synergistic qualities found in our exceptional ingredients.