Oyster Shell is a high quality soil conditioner which consists of 96% calcium carbonate and many micro-nutrients. Ground Oyster Shell provides a long-lasting, steady release of nutrients to help regulate pH levels, promote healthy cellular structure, increases fertilizer uptake, and enhance soil tilth. Oyster Shell is also helpful in creating more active habitats for soil microbes in compost piles and worm bins. Highly beneficial when planted with tomatoes, peppers and eggplants. Application Rate: Apply 4 to 6 lbs per 100 sq.ft. Additional application rates included on package. Available in 6 lb box, 25lb or 50 lb bags. OMRI Listed & cdfa Registered.