Growth of Lettuce (Lactucasativa L.) Plant Under Red-Blue-White Light and Grow Light LEDs in Plant Factory System

Abstract

Indoor culture requires a variety of inputs to get maximum biomass. These inputs are the nutrients, temperature, humidity, and light which plants needed to photosynthesize. Different types of light have been studied and it is known that the same spectrum will give different responses by different plants. The purpose of this study was to find out the effect of red-blue-white light LED on lettuce growth compared to grow light LED as a control which commonly used in plant factory rooms. The red-blue-white light is arranged on a 100 cm long aluminum rod, mounted along the plant in a gully DFT hydroponic fed by 1000-2000 ppm nutrients of ABmix plus with a pH of 5.5-6.5. LED grow light provided the plant a significantly higher height of 16.30% compared to red-blue-white light, but was no different to the length of lettuce root. The number and the area of leaves in red-blue-white light were markedly higher at 16.67% and 33.78% respectively than grow light. In addition, the red-blue-white light increased the chlorophyll content, fresh weight, and dry weight of lettuce plants, by 25.00%, 101.49% and 58.13% consecutively. Therefore, these results suggested that the red-blue-white LED light provided a significant higher biomass than the grow light LED.