How to choose the right plant light

The need for supplementary lighting in the greenhouse

In recent years, with the accumulation and maturity of knowledge and technology, the plant growth lamp, which has always been regarded as a symbol of high-tech modern agriculture in China, has gradually entered people's field of vision. With the gradual deepening of spectral research, it has been found that different wavelengths of light have different effects on different growth stages of plants. 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.

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. Under the fixed environmental conditions such as carbon dioxide, water, nutrients, temperature and humidity, the "photosynthetic light flux density PPFD" between the light saturation point and the light compensation point of a specific plant directly determines the relative growth rate of the plant. Therefore, an efficient light source PPFD Combination is the key to plant factory productivity.

Light is a kind of electromagnetic radiation. The light that can be seen by the human eye is called visible light, 380nm to 780nm, and the light color ranges from violet to red. Invisible light includes ultraviolet light and infrared light. Photometric and colorimetric units are used to measure the properties of light. Light has both quantitative and qualitative properties. The former is light intensity and light period, and the latter is light quality or light harmonic energy distribution. At the same time, light has particle properties and wave properties, that is, wave-particle duality. Light has visual properties as well as energy properties. Basic measurement methods in photometry and colorimetry. ① Luminous flux, unit lumen lm, refers to the sum of the amount of light emitted by a luminous body or light source in a unit time, that is, the luminous flux. ②Light intensity: symbol I, unit candela cd, the luminous flux emitted by a luminous body or light source within a single solid angle in a specific direction. ③ Illuminance: symbol E, unit lux lm/m2, the luminous flux of the illuminant irradiated on the unit area of ​​the illuminated object. ④Brightness: symbol L, unit Nitrel, cd/m2, luminous flux of luminous body in unit solid angle and unit area in a specific direction. ⑤ Luminous efficiency: unit lumens per watt, lm/W, the ability of an electric light source to convert electrical energy into light, expressed by dividing the emitted luminous flux by the power consumption. ⑥ Lamp efficiency: also known as the light output coefficient, is an important criterion for measuring the energy efficiency of lamps and lanterns. It is the ratio between the light energy output by the lamp and the light energy output by the light source in the lamp. ⑦ Average lifespan: unit hour, refers to the number of hours when a batch of bulbs are damaged to 50% of the quantity. ⑧Economic life: in unit hour, considering the damage of the bulb and the attenuation of the beam output, the integrated beam output will be reduced to a specific number of hours. This ratio is 70% for outdoor light sources and 80% for indoor light sources such as fluorescent lamps. ⑨ Color temperature: When the color of the light emitted by the light source is the same as the color of the light radiated by the black body at a certain temperature, the temperature of the black body is called the color temperature of the light source. The color temperature of the light source is different, and the color of the light is also different. The color temperature below 3300K has a stable atmosphere and a warm feeling; the color temperature is between 3000 and 5000K, which is an intermediate color temperature, which has a refreshing feeling; the color temperature above 5000K has a cold feeling. ⑩ Color temperature and color rendering: The color rendering of the light source is indicated by the color rendering index, which indicates that the color deviation of the object under light compared with the reference light (sunlight) can reflect the color characteristics of the light source more comprehensively.

Arrangement of fill light time

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

Choice of grow lights

The scientific choice of light source can better grasp the speed and quality of plant growth. When using artificial light sources, we must choose natural light that is closest to the conditions for plant photosynthesis. Measure the photosynthetic luminous flux density PPFD (Photosynthetic PhotonFlux Density) produced by the light source to the plant, grasp the rate of plant photosynthesis and the efficiency of the light source, and the amount of photosynthetically effective photons in the chloroplast to initiate the photosynthesis of plants: including light reaction and subsequent dark reaction.

Plant grow lights should have the following characteristics

1. Efficiently convert electrical energy into radiant energy. 2. Achieve 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.

Plant fill light principle

LED plant fill light is a kind of plant light, which uses light-emitting diode (LED) as the light source and replaces sunlight with light according to the law of plant growth to create a plant growth and development environment. LED grow lights help to shorten the growth cycle of plants. The light source is mainly composed of red and blue light sources, using the most sensitive light bands for plants. The red light wavelengths use 630nm and 640-660nm, and the blue light wavelengths use 450-460nm and 460-470nm. These light sources can allow plants to produce the best photosynthesis, so that plants get the best growth state. 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.