ASHS 2015 Annual Conference

Growing green vegetable is limited by the availability of light in cold countries. Increasing population and the demand for fresh, quality green vegetables have been the major concerns about using efficient light technology, which can be used 365 days in a year. Light emitting diodes (LEDs) is the best choice over a conventional lighting system. These lights generate lesser heat, require less power supply, and have the ability to customize the required intensity and the wavelength (light spectrum) with efficient light quality and longer life span. Overall, LEDs play a very important role in urban agricultural economy. The objective of this study is to determine the effect of different wavelength and light intensity ratio on the growth of 'Breen' lettuce using a circulating hydroponic system. The lettuce was grown in the lab, under a combination of wavelengths: 640nm, 450nm, and 590nm (red, blue, and amber), and 24 different light intensity ratios. At the end of the experiments, significant results will be analysed, such as, variations in fresh weight, dry weight, root length, and leaf area. Pigment analysis of total carotenoids, Chl-A, Chl-B, and anthocyanin, will be analysed for every intensity ratio. In conclusion, the screening method will provide the information of plant response to different light intensity ratios. The optimized light ratio can be economic and produces the better quality and quantity of lettuce in an urban agriculture method.