Our Crustacean & Calcium Blend is an all-natural combination of ground seashells and shrimp meal. Crustacean and Calcium Blend [500g] Dr Greenthumbs Crustacean & Calcium Blend is an all-natural combination of ground seashells and shrimp meal. The blend is used to deliver fast and slow release calcium to your soil, along with a vast range of natural minerals and soil enhancers. Dr Greenthumbs Crustacean & Calcium Blend contains a premium source of Chitin, which when broken down in the soil and around plant roots, triggers the production of a natural enzyme within the plant (Chitinase) which repels pests and detrimental fungal outbreaks such as powdery mildew. Use at 1/2 - 1 cup per meter squared. Size: 500g Includes: 1x Crustacean and Calcium Blend