Sheet, board or panel, in particular an OSRB (1)—Oriented Structural Reed Board—comprising a layer of material (2) made up of pressed reeds having a multiplicity of stems which are split predominantly longitudinally, so that it is also the case that the insides of the stems, at least in part, are accessible to a binder, wherein the binder is able to hold together the reeds for forming a solid sheet, board or panel. It is thus possible to provide a biocomposite sheet, board or panel based on sustainable raw materials which has improved properties and strength and requires only a particularly low level of production outlay. A further aspect of the invention relates to a method for producing an OSRB (1).