A system for the transverse movement, centralised and with limited effort, of the covering sheets and/or nets of the protection structures (G, G') of rows (F) of plants, wherein each sheet has a longitudinal side (104) secured to the longitudinal cable (2) of a related row and has the other longitudinal side (204) movable and for this purpose provided with rings or other suitable means (5) to be able to run on the fixed transverse cables (3) of said structures (G, G') and, always for the purpose of movement, this side (204) is secured to transverse pulling cables (7), positioned above and preferably at a height slightly greater than the height of said fixed transverse cables (3) and of the fixed longitudinal cables (2) of the structures (G, G') so as not to interfere with these fixed cables (2, 3). Below the sheets (4) there are provided supplementary and at least flexible cables (14), all or part of which can be fixed, but which are preferably movable together with and in the same direction as the pulling ca
