A system for covering crops arranged in rows, such as, by way of non-exclusive example, rows of grapevines, of the type comprising a plurality of sheets or nettings (4) made of plastic material, said sheets being in the form of parallel strips joined together along the edges so as to form a continuous cover, said sheets (4) being supported by ropes (6) stretched horizontally along the rows and over them, wherein: said sheets (4) are laid on said ropes (6) along their own midline； said ropes (6) are housed on the top of a plurality of posts (2) arranged in a straight line, in positions corresponding to the rows； each post (2) is equipped with means designed to retract a corresponding part of said strips made of transparent plastic material towards their midline in such a way that wide spaces are opened between said strips so as to air the underlying crops； said system being characterized in that said means designed to retract said sheets (4) towards their midline comprise a flexible cord that winds round said strips, said flexible cord forming a loop (7) at each of said posts (2), in such a way that by closing said loop (7), the cover is retracted towards the midline of the strip (4), where the ends (7a, 7b) of said loop (7) pass through a hole or ring set in the proximity of the top of said posts (2)； wherein said ends (7a, 7b) are fixed to a single control wire (8) purposely stretched horizontally along each row so that all the ends can be pulled via said rope (8) to tighten the respective loops (7).L'invention concerne un système de couverture de cultures agencées en rangs, telles que, de manière illustrative non exclusive, des rangs de vignes, du type comprenant une pluralité de feuilles ou de filets (4) en matière plastique, lesdites feuilles étant de la forme de bandes parallèles jointes ensemble le long des bords de façon à former une couverture continue, lesdites feuilles (4) étant supportées par des cordes (6) étendues horizontalement le long des rangées et
