Down to Earth Organic Rock Phosphate Fertilizer is a natural and organic source of phosphorous for plants. It is a 0-3-0 formula, which means it contains 0% nitrogen, 3% phosphorous, and 0% potassium. The 5 lb package is designed for use in both indoor and outdoor gardens. It is ideal for promoting root growth, fruit and flower development, and overall plant health. This product is made from mined rock phosphate and is a long-lasting source of phosphorous, which helps to improve soil fertility over time. It is an OMRI Listed product, which means it has been deemed safe and effective for use in organic production by the Organic Materials Review Institute. This fertilizer is ideal for use in vegetable gardens, flower gardens, and for growing fruit trees.