The shells of crustaceans have two benefits for biological gardeners. They are largely made of calcium carbonate. There is a bit of phosphorus, nitrogen and magnesium in there- but it is the calcium carbonate they contain that is of value to us. This calcium comes without the extra sulphur, as in gypsum, or the extra magnesium, as in dolomite. This is an important factor for the not till gardener, who wants a continuous calcium supply without the burden of excessive amounts of the other nutrients.
But layered between the calcium layers is a material that is very common in crustacean and insect shells, called chitin. In the form contained within the crab shell itself, chitin is of little benefit. However, as the shell particles are broken down by the soil microbes, the chitin is transformed into chitinase. This material has unique benefits, as it is a natural bio pesticide which boosts the innate ability of plants to defend themselves against fungal infections. In addition, chitosan increases and promotes plant growth, boosts plant vigor and actually destroys cyst nematodes in the root zone without endangering beneficial nematodes and organisms.
Our crab meal is ground to the finest particle size available, as this increases the surface area of the material greatly, and equally speeds up the decomposition of the material in the soil.
This product is approved for organic use.
Typically for soil building or top dress – ½ cup per 28ltr of soil but you should consult a certified agronomist with regards to crab meal and its application rates specific to your needs.