The Effect of Light Wavelength, Light Reflector, and Renewable Energy on Tagetes erecta L. Mass Growth Characteristics in Vegetative and Reproductive Stages

Abstract

           Light Emitting Diodes (LEDs) are the most suitable device for use as a light source to replace sunlight in Plant Factory. From testing samples of Full Spectrum LED lamps, it was found that in the Photosynthetically Active Radiation (PAR), LEDs lamps had the same full spectrum as sunlight but the consistency of the light photons in each wavelength is less, The distribution of light into the planting area is centralized and can't control light scatter at the edge, And most of the full spectra LEDs are devices that require AC power. So, The objective of this research is to study the effect of light wavelength, light reflector, and renewable energy on the plant's mass growth characteristics by using the LEDs lamps with R: G: B = 1.11: 1.20: 1.00, R: G: B = 2.04: 2.12: 1.00, R: G: B = 1.47: 1.83: 1.00 and R: G: B = 2.53: 2.67: 1.00 combination with light reflectors tilted 60 and 90 degrees from the ground plane. And compared a power system between solar cell DC power and main AC power. Tagetes erecta L. (Marigold) was selected as a specimen plant due to the high-intensity light requirement.
          The results of this research shown that 1) In the vegetative stage, LEDs with R: G: B = 1.11: 1.20: 1.00 had the best effect on a root, shoot, leaf, and flower mass, In the reproductive stage LEDs with R: G: B = 2.04: 2.12: 1.00 had the best effect on root and leaf mass, And LEDs with R: G: B = 1.11: 1.20: 1.00 had the best effect on shoot and flower mass. 2) In the vegetative stage, planting with a 60-degree light reflector producing more leaf mass, In the reproductive stage, planting with a 60-degree light reflector producing more root, shoot, leaf and flower mass 3) In the vegetative stage, planting with a solar DC power was no significant difference in root and flower mass, In the reproductive stage, planting with solar DC power was no significant difference in shoot mass.