The light sources suitable for plant supplementary lighting include: high pressure sodium lamp, metal halide lamp, ceramic metal halide lamp, microwave sulfur lamp, plasma lamp, fluorescent lamp, electrodeless lamp, three primary color rare earth supplementary light lamp, led Grow light, etc. The most commonly used are sodium lamp, metal halide lamp and led Grow light. Others are small or expensive.
High pressure sodium lamp can be divided into ordinary sodium lamp, high luminous efficiency sodium lamp and plant supplementary light sodium lamp. The commonly used ones are 250W, 400W, 600W and 1000W. At present, the trend is that the higher the power, the better, because it is very simple, a set of 1000W system is cheaper than two sets of 400W system, with large coverage and good effect.Ordinary sodium lamp is cheap, low luminous flux, high luminous efficiency sodium lamp, as the name implies, luminous flux is higher, but these are not real plant supplementary light sodium lamp, only used as street lamp.
The sodium lamp for plant supplementary lighting must have correct spectrum and high lumen output; although the high luminous efficiency sodium lamp has high lumen output, the content of red and blue light in the spectrum is much lower than that of the plant sodium lamp, and the useless green light is 7-9 times higher than that of the plant sodium lamp, which can only be a waste of energy under the effect. That’s why some customers ask why the growth effect is not obvious, you use the wrong lamp.
In order to judge the high luminous efficiency sodium lamp and the plant sodium lamp, we can only use the spectrum analysis, but there is no method to judge with the naked eye at present. This is also the reason why many factories can deceive the vast number of growers unscrupulously and bring losses to consumers.
Metal halide lamp contains rich blue light, and even the plant sodium lamp with spectral reinforcement contains much less blue light than metal halide lamp. Sodium lamp and metal halide lamp can achieve a perfect effect when used together. However, considering the cost, sodium lamp is still used in greenhouse. Buy metal halide lamp to be careful of bad merchants, with metal halide lamp shell is actually mercury lamp, the price is very low.
The production technology and products of three primary rare earth supplementary lamps were first introduced to the mainland from Taiwan. Its working principle is the same as fluorescent lamp. After the lamp is electrified, it emits electrons and mercury vapor in the lamp tube to form an internal circuit. After the mercury atom in the lamp tube collides with the inert gas, the ultraviolet light is excited at 253.7nm, which is absorbed and converted into visible light by the trichromatic phosphor containing some rare earth elements. The light quality combination of the three primary color rare earth supplementary light lamp is relatively fixed and can not be adjusted at will. The photosynthetic effective radiation energy in the light is relatively low. Therefore, it can not meet the needs of different plants or plants for different light quality combinations (photosynthetic nutrition) in different periods, and can not meet the rigorous requirements of scientific research and experiment in the field of plant photosynthesis. Therefore, the scope of application is relatively small and comprehensive supplementary light is required The effect is average. In addition, the manufacturing material and technology of this lamp determine that it is fragile and harmful to the use environment. The leakage of highly toxic mercury vapor will permeate plants and human body with the air falling, which is harmful to health, especially to pregnant women, infants and the elderly. Therefore, this kind of fill light is not suitable for use in the environment of small space and many people such as home and office. At present, the market of three primary color rare earth supplementary lamps is too chaotic, the quality is uneven, and the products with excellent effect are very few. In addition, the purchase and later use and maintenance costs are high (relatively high power, relatively short life), limited use, poor effect and other factors, so the current application scope is very small.
Led Grow light is a new high-tech product rising with white LED lighting in recent five years. The experiment about the influence of different LED light quality on plants in many domestic research institutes has only started or completed in recent years. The light quality of LED Grow light is determined by chip, but the quality of domestic chip used in current Grow light is not up to standard, so we can only choose LED lamp beads packaged by imported chip to produce LED Grow light, which leads to high cost of lamp production. However, due to its accurate light quality and artificial combination adjustment, high photosynthetic radiation per unit power consumption, good plant light compensation effect and low operating cost (super power saving), it is favored by agricultural research institutes and intelligent plant factories all over the world. However, since 2012, some private handicraft workshops have joined the lamp manufacturing camp. These people do not understand agricultural technology, do not have product experimental conditions, do not consider the safety issues, just purchase components to assemble at will, the price of finished products is super cheap. The so-called “led Grow light” with poor quality and no effect is disturbing the original difficult market environment, which is also the current situation of white LED market. Therefore, when choosing led Grow lights, we should also polish our eyes. It is better to choose products built before 2012 with quality assurance, brand and reasonable price. We should not be greedy for cheap and suffer huge economic losses and safety accidents.
Different plants have different requirements for spectrum. For example, lettuce is red / Blue 4:1, strawberry 5:1, and universal 8:1. Some plants need to add infrared and ultraviolet rays. However, some factories have little knowledge and put all the spectra together. The name “full spectrum” is suitable for any plant. As a result, because it contains ultraviolet rays, it can kill orchids. Fortunately, it is not hundreds of thousands of them. White light contains all the spectrum, so someone has a whole white LED, say full spectrum. But I did an experiment, the same plant, using two 200W white light, while using a 90W UFO (red and blue 1:1) and 90W square (red and blue 8:1). After a week, plants under white light obviously grow slower than those with red and blue lights. Don’t be superstitious about white light. At most, add a few white LEDs in the red and blue light to improve the use, rather than as the main lamp.
The output lumen of LED is not high. Some customers say that Philips is useless, because the maximum T-tube lamps of Philips are only 20W, and a frosted lampshade is added, and some lumens are lost. How many micromoles can be left when it is hung high on the plant? It’s strange that it works. Led Grow lights with less than 50 watts are suitable for use close to plants, which are more suitable for plant tissue culture (layered planting), family cultivation of flowers and vegetables, small space soilless cultivation and other fields, while the LED Grow lights with more than 50 watts are suitable for greenhouse use, and the lamp distance from the main crown area of crops should be controlled within 2.5 meters.