Island Phosphate Hi P 0-11-0 (5 lb Box)Seabird guanos have been used as a fertilizer for thousands of years; collected from the abandoned roosting areas of migratory birds. Seabird guanos high in phosphorus (fossilized) are from deposits accumulated over hundreds of years. The phosphorus is readily available and the high humus content makes it an excellent soil builder. Effectiveness is maximized by foliar application. Work or water it into the soil at 5 lb 100 sq ft. Use it as a foliar