The name ‘calçot' comes from the way they are cultivated: the white onion shoots are replanted and successively covered over with soil as they grow, an action known in Catalan as ‘calçar' (to wedge). The result is a tender white shoot around 15 to 25cm long that has a sweet, strong taste. The calçots protected by the PGI (Protected Geographical Indication) are the Blanca Gran Tardana variety.
They are sold in bundles of 25 to 50 that are tied up with marked tape bearing a numbered label that must be approved by the Board (Consell). In addition to the current legal requirements, the label must bear the name 'Calçot de Valls. Indicació Geogràfica Protegida' and the PGI logotype. They are sold in greengrocers, particularly in the production area, when they are in season.