【Encyclopedia】Detailed introduction of plant growth lights

The plant growth light is a special kind of lamp used on the plant growth rack. According to the law of plant growth, sunlight must be required, and the plant growth light is a lamp that uses the principle of sunlight to replace sunlight for the growth and development environment of plants. .

Basic information

Name: Grow Light, the light replaces sunlight for the growth and development of plants

Function: Promote growth, prolong flowering period, and improve quality. After application testing, the wavelength of plant light is very suitable for plant growth, flowering and fruiting. Generally, indoor plants and flowers will grow worse and worse with time. The main reason is the lack of light. Irradiation, irradiated by LED lights suitable for the spectrum required by plants, can not only promote their growth, but also prolong the flowering period and improve the quality of flowers.

The application of this high-efficiency light source system to agricultural production such as greenhouses and greenhouses can, on the one hand, solve the drawbacks of the lack of sunlight leading to the decrease in the taste of greenhouse vegetables such as tomatoes and cucumbers. It will be listed before and after the Spring Festival, so as to achieve the purpose of off-season cultivation.

1. As a supplementary light, the light can be enhanced at any time of the day, which can prolong the effective lighting time.

2. Whether at dusk or at night, it can effectively extend and scientifically control the light required by plants.

3. In the greenhouse or plant laboratory, it can completely replace natural light and promote plant growth.

4. Completely solve the situation of watching the sky and eat in the seedling stage, and arrange the time reasonably according to the delivery date of the seedlings.

The significance of greenhouse lighting

The growth rate of plants depends on the light intensity, that is, the amount of light radiant energy absorbed by the surface of the plant, not on the number of light sources.

The significance of lighting inside the greenhouse is to extend enough light intensity throughout the day. Mainly used for growing vegetables, roses and even chrysanthemum seedlings in late autumn and winter. Greenhouse lighting has a huge impact on the growth period and seedling quality. Usually, for tomatoes, light will start after the plant seedlings grow two cotyledons. Continuous light for 12 days can reduce the seedling preparation period by 6-8 days. But more than 24 hours of light will cause plant growth disorder.

The most suitable light time is 8 hours a day. Artificial lighting is a must on cloudy and low-intensity days. Give crops at least 8 hours of light per day at night, and the time of day should be fixed. But lack of nighttime rest can also lead to disordered plant growth and reduced yields.

For tomatoes, the most effective light time is from dusk to midnight, 16: 00-24: 00 or from midnight to early morning 24: 00-8: 00. This is 8 hours of light and 8 hours of rest. In practice, we should provide light to plants throughout the growing period, ie from seedling to colonization. In the final period, we should reduce the light to 6 hours a day or even stop it for 2-3 days. If it takes a long time to the colonization period because of poor light conditions, the light usually lasts for a month.

The choice of light source

When using artificial light sources, we must choose natural light that is closest to the conditions for photosynthesis in plants. The light source should have the following characteristics:

1. Efficiently convert electrical energy into radiation energy;

2. Reach high radiation intensity within the effective range of photosynthesis, especially low infrared radiation (thermal radiation);

3. The emission spectrum of the bulb meets the physiological requirements of plants, especially in the effective spectral region of photosynthesis.

Compared with various artificial light sources whose intensity is in the effective region of photosynthesis and emits horizontally, the energy conversion effect of sodium lamp is twice as high as that of mercury lamp.

Sodium lamps are the most effective light sources in the greenhouse that affect plant photosynthesis and correct growth. Tubular sodium lamps can achieve high luminous efficacy radiation of 1501m/w, and are currently the most favorable choice for the growth of various crops. Increasing the sodium vapor pressure in the ceramic arc tube broadens the spectrum of blue and red light, which is the high range of wavelengths sought.

Their difference lies in boosting a higher 0-40% blue light range, activating the plant’s chlorophyll. In order to obtain the highest radiant energy, all sodium lamps are side-mounted in the lampshade. A reflective layer is applied. At present, most factories in China generally use sodium lamps as street lamps for plants on the spot, and export them, causing a lot of losses to the majority of users.

The principle

Light environment is one of the important physical environmental factors that are indispensable for plant growth and development. Controlling plant morphogenesis through light quality regulation is an important technology in the field of facility cultivation.

Effects of spectral range on plant physiology:

280nm ~ 315nm has little effect on morphology and physiological process;

315 nm~420 nm chlorophyll absorbs less, which affects the photoperiod effect and prevents stem elongation;

420 nm~ 500nm (blue) Chlorophyll and carotenoids have the largest absorption ratio and have the greatest impact on photosynthesis;

The absorption rate of pigments from 500 nm to 620 nm is not high;

620nm ~ 750nm (red) The absorption rate of chlorophyll is “high”, which has a significant impact on photosynthesis and photoperiod effects;

The absorption rate of 750nm ~ 1000nm is low, which stimulates cell extension and affects flowering and seed germination;

> 1000nm is converted into heat.


The wavelengths are rich in types, which are exactly in line with the spectral range of plant photosynthesis and photomorphogenesis; the half-width of the spectral wave is narrow, and pure monochromatic light and composite spectrum can be obtained by combining as required, and the light of a specific wavelength can be concentrated to irradiate crops in a balanced manner. It can not only adjust the flowering of crops It can be used for multi-layer cultivation and three-dimensional combination system, realizing low heat load and miniaturization of production space.

Sunlight is a necessary factor for plant growth in addition to nutrients and water. But every grower knows that sunlight cannot be controlled. Therefore, artificial sunlight is more and more recognized in horticultural cultivation, because artificial sunlight can artificially control the season of plant growth and completely shorten the time of plant growth. Has the following uses:

1. As a supplemental light, the light can be enhanced at any time of the day so as to always assist the plant in photosynthesis. Especially in the winter months, the effective lighting time can be extended. No matter at dusk or at night, it can effectively extend and scientifically control the light required by plants, and is not affected by any environmental changes.

2. In the greenhouse or plant laboratory, it can completely replace natural light to promote plant growth. For the vast majority of growers, plant sodium and metal halide lamps are the best light sources to replace sunlight. Metal halide lamps are rich in blue light, which is suitable for the growth of early plant branches and leaves, and agricultural sodium lamps are rich in red and orange light, which has a positive effect on promoting plant flowering and fruiting.

To sum up, with the rapid development of facility horticultural area, the light environment control lighting technology for plant growth has attracted attention.