The research on LED supplementary lighting system for plants

As an artificial light source, light-emitting diodes (LEDs) can be used to make the vegetables grow more quickly in closed-type plant production systems, especially in the environment of the light intensity is insufficient. In order to study the improvement of the cherry tomato growth rate using the LED light source, we have a design with a certain ratio of red and blue (relative spectral distribution) LED lighting system and carry out the manufacture of the LED supplementary lighting system. We carried on a track on the growth situation for a group of cherry tomatoes under the LED system and the other group of cherry tomatoes without the LED supplementary lighting system. We observed and compared with the growth of the two group of tomatoes in different growing period. In our experiment, we use supplementary lighting system with the red and blue LEDs which peak wavelenth are respectively 650 nm and 460 nm, and the relative spectral distribution ratio is 4:1. The experimental results showed that the LED supplementary lighting system significantly improved the growth speed of tomatoes. Because of the difference preference for the wavelength between the stem and leaf growth stage and the blooming and bearing fruit growth stage, this paper presents the red and blue light proportion choice switch which can be applied to the LED supplementary lighting system. (C) 2016 Elsevier GmbH. All rights reserved.