The Influence of Light Wavelengths Toward the Growth of Brassica rapa L.

Abstract

This research aims to analyze the influence of wavelength from light source on growth of Brassica rapa L (pak choi). The lamps used in the research were 11-watt UV light, 8-watt white LED light, red LED light, green and blue 3-watt LED lights, and 150-watt infrared light, placed in boxes except infrared one. The irradiation was done in the growth box made from cardboard with size of 23 cm × 27 cm × 40 cm for 9 hours every day. The measurement done was a biometric measurement by measuring stem height, leaves width and their numbers. The observations were done for 14 days starting from the first day of planting. From the measurement result, the pak choi can grow well on white LED light. While in other light sources, it cannot grow well due the lack in wavelength needed by the plant. The experiment was further carried out by combining white LED light with blue, red and UV. The growth box was made larger with a size of 40 cm × 27 cm × 46 cm. The experimental result showed that all pak choi plants can grow well. Light using a combination of lights was useful in the development and the growth of pak choi. From the three treatments, pak choi with white LED light and UV showed faster growth for width, length and number of leaves.