1. Red and blue wavelength ratio of LED plant light wavelength
As the two main absorption areas of plant photosynthesis, the spectrum emitted by LED plant lights should be dominated by red light and blue light. But it cannot be simply measured by the ratio of red and blue. Plant species vary widely and have different habits, and different growth stages also have different light emphasis requirements. The spectrum required for plant growth should be a continuous spectrum with a certain distribution width. It is obviously inappropriate to use a light source made of two specific wavelength chips, red and blue, with a narrow spectrum. In the experiment, it was found that the plants will be yellowish, the leaf stems are very light, and the leaf stems are very thin and so on. There have been a lot of studies abroad on the response of plants to different spectra, such as the effect of the infrared part on the photoperiod, the effect of the yellow-green part on the shading effect, the effect of the purple part on the resistance to diseases and insect pests, nutrients, etc. In practical applications, seedlings are often burned or withered, so the design of this parameter must be designed according to the plant species, growth environment and conditions.
2. LED plant light ordinary white light and full spectrum
Plants "see" light effects differently than the human eye. The white light lamps we commonly use cannot replace the sun’s light, such as the tri-color white light tubes widely used in Japan, etc. The use of the spectrum of these agricultural growth lights has a certain effect on the growth of plants, but the effect is not as good as that made by LEDs. The light source is good. For fluorescent tubes with three primary colors that have been widely used in the past few years, although white is synthesized, the red, green, and blue spectra are separated, and the width of the spectrum is very narrow, and the spectral intensity of the continuous part is relatively weak. , At the same time, the power is still relatively large compared to LEDs, etc., 1.5~3 times the energy consumption. The LED full spectrum specially designed for plant lighting optimizes the spectrum. Although the visual effect is still white light, it contains an important part of the light required for plant photosynthesis.
3. LED plant light intensity parameters
The light quantum flux density is an important parameter to measure the illumination intensity of LED plant lights. It can be represented by light quanta or radiant energy. The light compensation point of plants means that PPFD needs to be higher than this point, so that photosynthesis can be greater than respiration, and plant growth is greater than consumption, so that plants can grow. Different plants have different light compensation points, and we cannot simply think that reaching a certain index is enough. The light intensity reflected by the illuminance meter used in the past is brightness, but because the spectrum of plant growth changes due to the height of the light source from the plant, the coverage of the light, and whether the light can pass through the leaves, etc., it is used as a light when studying photosynthesis. Strong indicators are not accurate enough, and PAR is mostly used now.
4. LED plant lighting formula
LED plant lighting formula is a new concept recently proposed, which mainly includes three factors: light quality, light quantity and duration. Simply understood, light quality is the spectrum most suitable for plant photosynthesis; light quantity is the appropriate PPFD value and uniformity; duration is the cumulative value of irradiation and the ratio of day and night time. The study found that plants judge the cycle of day and night through the ratio of infrared and red light. At sunset, the ratio of infrared light increases significantly, and plants respond quickly to sleep. Without this process, plants would take hours to complete the process.