E.B. Stone Organics Bat Guano is a readily available source of nitrogen, phosphorous and potash. It is highly recommended as a ‘plant tea’ fertilizer and excellent for container gardening and outdoor plants. E. B. Stone Organics Bat Guano is also ideal for use whenever nitrogen is needed in the garden. Use it to encourage growth and to enhance the color of plant foliage. NPK: 7-3-1 Derived from: Bat Guano.