A plastic covering film, of polyethylene base, for covering agricultural beds, consists of two parallel tubes (2, 3) able to receive ballast e.g. water or earth, over all or part of their length, formed directly on not on the film (1) and extension boards (4, 5) over the length of the film of sufficient width (L1) to be buried in the soil of the pre-established furrows of the cultivated zone. Tear zones (6) along the film length, adjacent to the tubes allows separation when harvesting the crops. A free strong, cord or strand (7) is introduced into each tube (2, 3), at mfr. or later to allow anchorage of the film using spikes (8). The film is presented rolled on a mandrel, unrolled over the furrow to be covered, the edge boards buried then the film spiked through the ballast tubes to secure it. This can be done automatically.
