Additives for compost for ornamental plants and/or agricultural production plants in the form of granules comprising a) between 5 and 65% by weight on the total weight of the composition of a superabsorbent polymer, for agriculture (SAP), b) between 35 and 70% by weight on the total weight of the composition of a hygroscopic material essentially of vegetable origin； c) between 20 and 40% by weight on the total weight of the composition of a natural plasticizer of mineral or vegetable origin.
