To answer this question, in winter 2014-2015 a practical test was conducted on the influence of improved light spectrum on the production and quality of the rose Avalanche. For this purpose, a part of the business was exposed with a hybrid arrangement of 103 µmol SON-T and Valoya LED lamp G1. This lamp is specially developed to be used in rose as a complement to SON-T.
LED lights with two different intensities were used: 57 and 103 µmol (one or two string of lights per bed). The test was carried out by Wageningen UR Greenhouse Horticulture, Plant Dynamics and employees of the business practice. In comparison with the conventional installation of the company (191 µmol SON-T), the modified spectrum purveyed, depending on the intensity of the added LED exposure, a 7- 9% higher light utilization efficiency by the crop. This offers prospects for energy efficiency.
Many measurements have been taken to find an explanation for this positive effect : photosynthesis, stomatal resistance, leaf color, bud temperature, leaf area, etc., but without result.
Additional studies on light color effect
It is recommended that additional research into the effects of light color on rose be conducted. The questions are whether other rose varieties will react equally positively on the modified spectrum, whether the crop can be more compact with a higher proportion of blue or if with more far red, light flowers become heavier, with a larger flower bud. And equally importantly: what is the physiological explanation for this result?
This project is funded by the program Kas als energiebron, innovation and action program of LTO Glaskracht Nederland and the Ministry of Economics.
Source: Kas als energiebron