Industrialization and metropolitanization in the modern times lead us to indoor farming of increasingly more plants using artificial lightings such as red, blue and white LEDs, but will the artificial lightings grow plants as well as the sun does?
Indoor farming facilities such as greenhouses and plant factories do not allow completely intact sunlight to reach plants. Therefore, currently the grow light for plants closest to sunlight is materialized only by SunLike of Seoul Semiconductor (Figure 1).
Figure 1 Spectra of SunLike of Seoul Semiconductor (left) and white LED (right).
The red dotted line is the spectrum of sunlight.
Note that the spectrum of SunLike is very close to that of sunlight.
Then, what differences will SunLike make in plant properties compared to other artificial light sources? Young lettuce plants were test-grown under SunLike and white LEDs for comparison, the latter of which is quickly becoming the global lighting trend at the moment (Figure 2).
Figure 2 Lettuce grown from young plants for two weeks under white LEDs and SunLike.
(b) The level of flavonol in lettuce leaves measured with Dualex (no unit).
Can you see the difference?
Lettuce grown under SunLike for only 2 weeks already gained more weight by 13.5%. The effect of SunLike was not limited to growth, but approved the nutritional quality. SunLike resulted in accumulation of 41% higher flavonol in plants compared to white LEDs.
It is still far from understanding all the effects of natural sunlight. However, considering plants have evolved to grow best under sunlight for the past tens of millions of years, it is certain that we are going to the right direction in using the light closer to sunlight in cultivating plants, and obviously, sunlight has had significant influences on everything on this planet.
Jinwon Kim, Ph.D.
* Next week’s topic : Light and Addiction (Endorphin Effects)