This invention relates to a plant protective cover of a translucent polymeric material including at least one transmission spectrum modifier for minimizing the transmission in the ultraviolet range up to 350 nm； and for adjusting the transmission in the visible light range between 350 nm and 750 nm in accordance with photosynthetic and photomorphogenic requirements of plants to be cultivated underneath the plant protective cover, to enhance the growth conditions of such plants. The cover further includes a transmission spectrum modifier for minimizing the transmission in the infrared range above 750 nm. The transmission in the visible light range between 350 nm and 750 nm is adjusted by decreasing the transmitted green and yellow wavelengths and by changing the ratio of blue to red wavelengths transmitted towards a 2:3 ratio. The cover optimises growing conditions for plants cultivated underneath the cover thus providing relatively enhanced plant growth and performance.
