The spectrum of LED grow lights

Different LED grow lights produce different spectra. Plant growth patterns can respond to the color spectrum of light. This process is completely separated from photosynthesis and is called photomorphogenesis.

Natural lighting has a high color temperature (about 5000-5800 K). The color of visible light changes according to the weather and the angle of the sun, and a specific amount of light (in lumens) stimulates photosynthesis. The distance from the sun has little effect on the quality and quantity of light in these seasons and the resulting seasonal changes in plant behavior. The axis of the earth is not perpendicular to the plane of the orbit around the sun. For half a year, the North Pole is tilted towards the sun, so the northern hemisphere is close to direct sunlight, while the southern hemisphere must travel through more atmosphere before reaching the surface of the earth. In the other half of the year, this is the opposite. The color spectrum of the light radiated by the sun does not change, only the quantity (more in summer and less in winter) and the quality of the entire light reaches the surface of the earth. Some complementary LED grow lights in vertical greenhouses only produce a combination of red and blue wavelengths. The color rendering index can compare the matching degree of light with the natural color of regular sunlight.
The ability of plants to absorb light varies with species and environment. However, the general measurement that affects the light quality of plants is the PAR value or photosynthetically active radiation.

There have been several experiments using LED grow lights to grow plants, and it has been shown that plants need red and blue light for healthy growth. It has been found in experiments that the leaves of plants grown only under red (660 nanometers) have poor deformation, but adding a small amount of blue can make most plants grow normally.