Neptune's Harvest Organic Crab & Lobster Shell (5-3-0) is an excellent dry organic source of nutrients, including calcium (17%) and magnesium (1%). It retains moisture in the soil and builds the organic matter. It also gives the roots something to grab onto and wrap around, for a food source, creating a deeper root system. Crab & Lobster Shell is high in chitin (kite-en), which promotes the growth of chitin eating bacteria in the soil. It will help eliminate ants, grubs, fungus and root nematodes, because they are all chitin based in structure. Put around plants, Crab & Lobster Shell will keep slugs and snails off. It also helps choke out weeds and keep moles, voles, mice, etc… from digging up bulbs and root vegetables. This product should be worked in the soil before planting, but may also be scratched into your topsoil. Our crab and lobster shells come from cold, clean, dark, mineral rich North Atlantic Ocean water, off the coast of New England.