Color temperature and lumens of biological light sources

The color temperature and lumens of artificial light sources are seen by the eyes of living things, while the demand of plants for light is photosynthesis, which is determined by the radiation value regardless of color temperature and lumens.

The effect of spectral range on plant physiology

280 ~ 315nm ––> This wavelength is already ultraviolet light, and it has the function of directly suppressing the growth of all kinds of animals, plants and even fungi, and has little impact on the morphological and physiological processes.
315 ~ 400nm ––> This light wave is also far ultraviolet light, although no ultraviolet rays harm plants, it has no direct effect on plant growth, and chlorophyll absorbs less, which affects the photoperiod effect and prevents stem elongation.
400 ~ 520nm (blue) –> These wavelengths can directly develop the roots and stems of plants, have the largest absorption ratio of chlorophyll and carotenoids, and have the greatest impact on photosynthesis.
520 ~ 610nm (green) –> Green plants are repelling and pushing, and the absorption rate of green pigment is not high.
610 ~ 720nm (red) –> The absorption rate of chlorophyll in plants is not high, but this wavelength has a significant impact on photosynthesis and plant growth rate.
720 ~ 1000nm ––> These wavelengths are generally infrared wavelengths, which have a low absorption rate for plants and can directly stimulate cell elongation, which will affect flowering and seed germination.
＞1000nm ––> It is close to the wavelength of laser light and has been converted into heat.
From the above plant and spectral data, each wavelength of light has different effects on plant photosynthesis. Among the light that plants need for photosynthesis, 400 ~ 520nm (blue) light, and 610 ~ 720nm (red) light for photosynthesis. Photosynthesis contributes the most, and 520 ~ 610nm (green) light has a very low efficiency rate for plant growth.

According to the above principle, the spectrum of plants only for 400 ~ 520nm (blue) and 610 ~ 720nm (red) has the effect of directly helping growth, so the plant lights under the academic concept are made of red and blue combination, all blue, full There are three forms of red to provide light with two wavelengths of red and blue, which are used to cover the wavelength range required by plants for photosynthesis.

In terms of visual effects, the red and blue LED plant growth lights are pink. This mixed light color is extremely uncomfortable for biological lighting. Sex is the main thing.

In general, white LED lamp beads, the most common one is to use a blue core to excite yellow phosphors to emit light, thereby producing a visual white light effect. On the energy distribution on the integrating sphere test report, there are two peaks in the blue region at 445 nm and the yellow-green region at 550 nm.

The 610 ~ 720nm red light required by plants is less covered and cannot provide light and the light efficacy required for the planting plants. This explains why the growth rate and harvesting effect of plants are not as good as those of ordinary outdoor planting under the illumination of white light LEDs.

Using the above data, the chromatographic ratio of red and blue lights of general plant lights is generally between 5:1 and 10:1, and the ratio of 7 to 9:1 is usually selected. The light basis, the number of non-lighting lamp beads is the light mixing basis.

When planting plants with led grow lights, the height from the leaves is generally about 30-50 cm. In the middle, it is still necessary to give different light intensities according to the type of plants. Adjusting the height is generally regarded as the easiest way to adjust the brightness.