It is an excellent dry organic source of NPK, calcium (23%) and magnesium (1.33%). Crab shell is high in chitin, which promotes the growth of chitin eating bacteria in the soil. When crab shell is added to the soil it helps to create a hostile environment for the fungus and nematodes by feeding the biological life. It will help eliminate Ants, Grubs, Fungus and Root Nematodes, because they are all Chitin based in structure. Put around plants, Crab 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.