A method and apparatus for a horticultural light system foruse in a greenhouse where aspects of ambient light in thegreenhouse are measured and compared against a prescribed lightrecipe. A light controller commands a light fixture containedwithin the greenhouse to augment the ambient light in responseto the comparison. Photosynthetic photon flux, light intensity,color temperature and color spectrum among other aspects oflight generated by the light fixture are altered by thecontroller to fill in deficiencies of the ambient light ascompared to the prescribed light recipe.
