Abstract: In indoor growing system uses roof mounted solar collector tubes that are supplemented with red and blue light emitting LED's. The LED intensity and intensity ratio is modulated in response to the chromatic variations in the solar energy reaching the plants that occurs season, time of day and weather conditions to optimize plant growth as well as product yield and quality. The LED intensity and intensity ratio is also temporally modulated in accordance with a plants growing cycle. The system enables space intensive agriculture with lower power and water usage, while producing higher quantity and quality output.