A method and apparatus for a horticultural light system for use in a greenhouse where aspects of ambient light in the greenhouse are measured and compared against a prescribed light recipe. A light controller commands a light fixture contained within the greenhouse to augment the ambient light in response to the comparison. Photosynthetic photon flux, light intensity, color temperature and color spectrum among other aspects of light generated by the light fixture are altered by the controller to fill in deficiencies of the ambient light as compared to the prescribed light recipe.
