Producing a targeted spectrum is touted as one of the biggest advantages of using LEDs in grow-lights. However, a little known fact is that the process by which the different colors are achieved can be as important as the final product.
To find why the process is important, it is necessary to understand the nature of light and how different colors in grow-lights are produced.
Light is electromagnetic radiation, and the different colors it consists of fall into different parts of its spectrum. The whole visible spectrum lies between the wavelengths 400 – 700 nm. The different colors each has a range of wavelengths as well (1).
Violet : 380-450 nm
Blue : 450-495 nm
Green : 495-570 nm
Yellow : 570-590 nm
Orange : 590-620 nm
Red : 620-750 nm
So there are different kinds of violet depending on the precise wavelength used; the violet at 380 nm is a different hue from violet at 450 nm (2).
Of these seven colours, RBG or red, blue and green, are called the primary additive colors, since any other color can be produced by mixing these three (3). If colour space can be imaged as the space formed by the three coordinates of red, blue and green, a hue is any point bound in this space. Making up the border of the color space are the seven colors in the light spectrum- violet, blue, green, yellow, orange, and red (4).
(Image credits: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/pricol2.html)
Usually, when LEDs are used, a set of LEDs of the primary colors RGB - red, green, and blue are used to get different hues. In this case, the hues are produced when the colors are mixed in the air (4, 5).
(Image credits: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/cie.html#c1)
Lumenari, however, avoids mixing colors in the air, as it decreases the lux that reaches the plant.
Lumenari’ diodes can turn to a precise hue, without mixing colors in the middle of the air. The result is that the light falling on the plant surface maintains its PPF, and gives the quoted PPFD, unlike other LEDs.
This is the crux, as Photosynthetic photon flux (PFF), is a measure of the light spectrum called Photosynthetic active radiation (PAR) that plants use. Photosynthetic photon flux density (PPFD), in turn, measures the amount of PFF that reaches the plant and which is absorbed by the plant surface.
Moreover, PPFD is a result of both wattage and hue. Lumenari provides the optimum PPFD everytime without the need to increase wattage to compensate for imprecise hue. This saves the use of additional watts and prevents an increase in expenditure.
PPFD = Wattage + Hue
By getting both hue and PPFD correct, Lumenari lighting ensures optimal absorption by plants and soil penetration and an overall better yield.
Not all LEDs are Equal
LEDs with technology that can supply the precise hue are the answer to avoid the pitfall of producing light that is not the right hue and therefore the prescribed PPFD. By using LEDs produced specifically for horticulture, as in Lumenari grow-lights, it is possible to provide the perfect targeted spectrum plants need, to increase yield and get better returns.