What bands of spectrum are needed for plant growth? Is plant growth lamp reliable?

According to the natural law of plant growth and the principle that plants use sunlight for photosynthesis, plant growth lamp is a lamp that uses light instead of sunlight to provide the light source required for plant growth and development.

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The sensitivity of plants to spectrum is different from that of human eyes. The most sensitive spectrum of human eyes is 555 nm, ranging from yellow to green light. It is less sensitive to blue light and red light. Plants are not. They are most sensitive to red light spectrum and less sensitive to green light, but the difference in sensitivity is not as great as that of human eyes. The most sensitive area of plants to spectrum is 400-700nm. This region of the spectrum is commonly referred to as the effective energy region of photosynthesis. About 45% of the energy of sunlight is located in this spectrum. Therefore, if the artificial light source is used to supplement the amount of light, the spectral distribution of the light source should also be close to this range.


The photon energy emitted by the light source varies with the wavelength. For example, the energy of 400nm (blue light) is 1.75 times that of 700nm (red light). But for photosynthesis, the effect of the two wavelengths is the same. The excess energy in the blue spectrum that cannot be used as photosynthesis is converted into heat. In other words, the rate of plant photosynthesis is determined by the number of photons that can be absorbed by plants in 400-700nm, which is not related to the number of photons sent out by each spectrum. But it is generally believed that the color of light affects the rate of photosynthesis. The sensitivity of plants to all spectra is different. This reason comes from the special absorption of pigments in leaves. Among them, chlorophyll is the most well-known. But chlorophyll is not the only pigment useful for photosynthesis. Other pigments are also involved in photosynthesis, so the photosynthetic efficiency cannot only consider the absorption spectrum of chlorophyll.



The difference of photosynthetic pathways is also not related to color. Light energy is absorbed by chlorophyll and carotene in leaves. Energy is converted into glucose and oxygen by two photosynthetic systems to fix water and carbon dioxide. This process uses the spectrum of all visible light, so the effects of light sources of various colors on photosynthesis are almost the same.Some researchers believe that the red part of orange has the greatest photosynthetic capacity. However, this does not mean that plants should be cultivated in this monochromatic light source. For the morphological development and leaf color of plants, plants should receive various balanced light sources.Blue light source (400-500nm) is very important for plant differentiation and stomatal regulation. If there is insufficient blue light and too much far red light, the stem will grow excessively, which is easy to cause leaf yellowing. The ratio of red spectrum (655 ~ 665nm) energy to far red spectrum (725 ~ 735nm) energy is between 1.0 and 1.2, and the plant development will be positive growth. However, the sensitivity of each plant to these spectral proportions is also different.

High pressure sodium lamp is often used as artificial light source in greenhouse. Taking Philips Master SON-TPIA lamp source as an example, it has the highest energy in the orange spectral region. However, the energy of far-infrared light is not high, so the energy ratio of red light / far-infrared light is greater than 2.0. However, because the greenhouse still has natural sunlight, it does not cause the plants to become shorter. (if this light source is used in the growth chamber, it may have an impact.)

Under natural sunlight, blue light energy accounts for 20%. For artificial light sources, such a high proportion is not required. For normally developing plants, most plants only need 6% blue light energy in the range of 400-700nm. In the natural sunlight, there is enough blue light energy. Therefore, the artificial light source does not need to supplement more blue spectrum. However, when the natural light source is insufficient (such as winter), the artificial light source needs to increase the blue light energy, otherwise the blue light source will become the limiting factor of plant growth. However, if the improvement method of light source is not used, there are still other methods to remedy the problem of insufficient light source. For example, by temperature regulation or the administration of growth hormone.

We are a company specializing in the R & D and production of plant lamps. We have been engaged in the R & D, production and sales of industrial hemp plant lamps for more than 10 years. Our products have nearly 10 years of overseas export experience and qualification. It has a complete set of perfect and mature plant spectrum technology and plant lighting application scheme.

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