Protection system for the mechanized covering of plant crops which are usually planted in rows, of the type in which vertical poles (1) are arranged along the rows and have heights greater than those of the crowns of the plants to be protected, the poles being interconnected by longitudinal (3) and transverse (2) cables to form an overhead supporting lattice roof structure, the system comprising means for mechanizing the steps of extending flexible protective sheets (4) over the roof structure and removing them therefrom, characterized in that: the poles (1) are in a staggered or grid arrangement such that they are transversely aligned in even-numbered rows (F2, F4, etc.) only and in odd-numbered rows (F1, F3, etc.) only, the whole arrangement being such that the transverse connecting cables (2) intersect the longitudinal cables (3) alternately at points at which neither the transverse nor the longitudinal cables are supported by poles (1) in that the transverse cables (2) run above the longitudinal cables at the intersection points and in that each protective sheet (4) is arranged so that its median longitudinal part slides on the longitudinal cable (3), passing alternately over a support pole (1), where it is supported from below by the longitudinal cable and by the portion of transverse cable (2) which interacts with the pole, and subsequently passing under a transverse cable (2) at the point of intersection with the longitudinal cable where the sheet is supported solely by the longitudinal cable, the whole arrangement being designed to form a protective covering which is supported from below and above by the support cables (2, 3), and which is therefore able to effectively withstand even considerable atmospheric turbulence.