Introduction to Plant Lighting Fixtures

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, tri color rare earth supplementary lighting lamp, LED plant lamp, etc. The most commonly used are sodium lamps for plant supplementary lighting, metal halide lamps, and LED plant lamps. Others are relatively niche or very expensive.

High pressure sodium lamps can be divided into ordinary sodium lamps, high light efficiency sodium lamps, and sodium lamps for plant supplementary lighting. The commonly used ones are 250W, 400W, 600W, and 1000W. The current trend is that the higher the power, the better, because it is simple: one 1000W system is cheaper and has better coverage than two 400W systems.

Ordinary sodium lamps have low prices and low luminous flux, while high efficiency sodium lamps, as the name suggests, have higher luminous flux. However, these are not truly sodium lamps for plant supplementary lighting, they are only used as street lamps.

The sodium lamp used for plant supplementary light must have correct spectrum and high lumen output; Although high luminous efficiency sodium lamps have high lumen output, the content of red and blue light in the spectrum is much lower than that of plant sodium lamps. The useless green light is 7-9 times higher than plant sodium lamps, which can only waste energy under the effect. That's why some customers are asking why the growth effect is not significant. You used the wrong light.

To determine whether a high light efficiency sodium lamp or a plant sodium lamp can only be determined through spectral analysis, and there is currently no method to determine with the naked eye. This is also the reason why many factories are able to deceive farmers without restraint and cause losses to consumers.

Metal halide lamps contain abundant blue light, and even plant sodium lamps with spectral enhancement contain significantly less blue light than metal halide lamps. If sodium lamps and metal halide lamps are used together, they can achieve the same effect. However, considering the cost, sodium lamps are still mainly used in greenhouses. Be careful of unscrupulous merchants when purchasing metal halide lamps. The inner shell of the metal halide lamp is actually a mercury lamp, which is very affordable.

The production technology and products of three primary color rare earth fill lamps were first introduced to mainland China from Taiwan. Its working principle is similar to that of a fluorescent lamp. After the lamp is powered on, it emits electrons and forms an internal circuit circuit with the mercury vapor inside the lamp. The mercury atoms inside the lamp tube discharge after colliding with inert gas, exciting 253.7nm ultraviolet light. The ultraviolet light is absorbed and converted into visible light by tricolor phosphors containing certain rare earth elements. The light quality combination of the three primary color rare earth fill light is relatively fixed and cannot be adjusted arbitrarily. The proportion of photosynthetic effective radiation energy in the light is relatively low, so it cannot meet the needs of different plants or plants for different light quality combinations (photosynthetic nutrition) at different stages, nor can it meet the rigorous scientific research and experimental requirements in the field of plant photosynthesis. Therefore, the scope of application is relatively small, and the comprehensive fill light effect is average. In addition, the manufacturing material and process of this type of lamp determine its fragility and pose a risk to the environment. The leakage of highly toxic mercury vapor can drift down with the air and penetrate into plants and the human body, posing a great threat to health, especially to pregnant women, infants, and the elderly. So, this type of fill light is not suitable for use in small spaces and crowded environments such as homes and offices. At present, the market for tricolor rare earth fill lamps is too chaotic, with uneven quality and very few products with excellent effects. In addition, high procurement and maintenance costs (relatively high power and short lifespan), limited use, and poor performance are factors that make the current application range very small.

LED plant lights are high-tech new products that have emerged in the past five years or so with the rise of LED white light lighting. Many domestic research institutes have only recently started or completed experiments on the effects of different LED light qualities on plants. The light quality of LED plant lights is determined by chips, and the quality of domestic chips used in current plant lights is not yet up to standard. Therefore, we can only choose imported chip packaged LED beads to produce LED plant lights, which leads to high production costs of lamps. However, due to its accurate and adjustable light quality, high photosynthetic radiation per unit power consumption, good plant light supplementation effect, and low operating costs (super energy-saving), it has many advantages. Since 2012, some private handicraft workshops have joined the manufacturing camp of lighting fixtures. These people do not understand agricultural technology, nor do they have the conditions for product experimentation, and do not consider safety regulations. They only purchase components and assemble them randomly, resulting in super cheap finished products. This low-quality and ineffective so-called "LED plant lights" are disrupting the originally difficult market environment, which is also the current situation facing the white light LED market. So, when choosing LED plant lights, it is also important to keep your eyes open. It is best to choose products that were built before 2012, have quality assurance, a brand, and reasonable prices. Do not seek cheap prices and suffer huge economic losses and safety accidents.

Different plants have different spectral requirements, such as red/blue 4:1 for lettuce, strawberry 5:1, and universal 8:1. Some require the addition of infrared and ultraviolet radiation, but some factories only have a partial understanding and combine all spectra together, claiming that full spectrum is suitable for any plant. As a result, because it contains ultraviolet radiation, it can kill the orchids, but fortunately it is not the kind that costs hundreds of thousands. White light contains all the spectra, so someone else created a white light LED that, when it comes to full spectrum, Philips did the same foolish thing. And I conducted an experiment on the same plant, using two 200W white lights on one side and a 90W UFO (red blue 1:1) and a 90W square (red blue 8:1) on the other. After a week, the plants under white light grew noticeably slower than those using red blue lights. Don't be superstitious about white light, at most add a few white LED lights to the red and blue lights for improvement, instead of using them as the main light. The output lumen of the LED itself is not high, and some customers say that Philips's T-tube lights are useless because Philips only has a maximum of 20W and has added a frosted lampshade, which has lost some lumens. How many micromoles are left when hanging from a high altitude and shooting onto plants? It's strange if there is an effect. LED plant lights below 50 watts are suitable for use near plants and are more suitable for plant tissue culture (layered planting), home flower and vegetable cultivation, and small space soilless cultivation. LED plant lights above 50 watts are suitable for use in greenhouses, and the distance between the lights and the main crop crown area should be controlled within 2.5 meters.