Grena is an Italian manufacturer of organic and organo-mineral fertilizers and amino-acid-based biostimulants. The company manages its production chain directly, including the meat meals used in its fertilizers, and has applied circular-economy principles since 1956. Its process uses thermal hydrolysis to transform animal- and plant-origin by-products into fertilizers and biostimulants. Grena highlights naturally present amino acids, polyamines and natural anti-stress properties among the characteristics of its products.

The range includes liquid and pellet biostimulants, organic fertilizers, soil amendments, corrective products, nitrogen fertilizers, and biological and NPK, NP and NK organo-mineral fertilizers. Named products include Idrogrena, Grena Ultra Micro, Grena Star N8, Grena Solo and Fertigrena. Products serve a broad range of crops and settings, including vegetables, fruit, vineyards, olives, cereals, flowers, lawns and home gardens. For hobby gardeners, Grena also offers solid, liquid and specialized products for plants such as citrus, orchids, roses and ornamental varieties. The company provides product information, crop guidance, customer assistance and access to agents and points of sale.