Rock phosphate, or Phosphorite, is mined from clay deposits that contain phosphorus and is used to make organic Phosphate fertilizers that many gardeners utilize. In the past, Rock Phosphate was used alone as a fertilizer, but due to a lack in supply, as well as low concentration, most applied fertilizer is processed. These nutrient-rich fertilizers work with the soil rather than against it as chemical fertilizers do. The nutrients are then made available to plants at a steady and even rate throughout the growing season and Azomite.The use of rock phosphate for gardens is a common practice for both flowers as well as vegetables. Flowers love an application of rock phosphate early in the season and will reward you with big, vibrant blooms.