A light-deprivation system includes shades having a fixed end that form a perimeter that defines a growing environment, cables attached to a free end of each shade, a cable guide located near a pinnacle of the light-deprivation system, and a winch to draw the shades. The cables run from the free end of each shade, through the cable guide, to the winch. Operation of the winch draws the shades simultaneously to block substantially all light from sources external to the growing environment from reaching the growing environment.