Light is energy. Plants are one of few organisms on earth that utilize light to run their production sites, and to create organic compounds. So when you think of lighting for your orchids, think of it as something that is harnessed to create plant material or blossoms. A plant can be viewed as a living, breathing "factory". When the factory is tiny it doesn't require much energy to function, but as it gets up to scale its energy needs increase. We have noticed that orchid seedlings start off best in lower light, less fertilizer and less water. As they mature they need more and more light.