Which light source is the best for plant growth?

Most of the green and yellow areas in the plant's reflectance spectrum are due to the color of the leaf itself Therefore, the best light sources for plants are blue and red When determining the best light source, indoor planters should consider the budget and the needs of specific plants Sunlight is the best light source for most plants because it can be obtained from the natural environment Plants grown outdoors are usually better than those grown indoors unless special techniques are used to mimic the light source of the external environment In some cases, plants exposed to direct sunlight in front of bright windows are just as good as plants planted under light But low light plants are an exception They can be burned by direct sunlight Fluorescent lamp researchers at the University of Kansas, Missouri, suggest using fluorescent lamp as the main artificial light source for indoor plants They have a long life span and can convert electrical energy into light, so they are relatively cheap Fluorescent lamps labeled as cold white or warm white are better than full spectrum or fluorescent lamps However, fluorescent lamps often lack the red spectral part of the light needed for plant growth, so compared with plants using light sources such as incandescent lamps, growers need to provide additional nutrients The plants that grow under the light of the metal halide lamp look very similar to those that grow outdoors Because metal halide lamps provide a large number of blue spectrum lights, their green leaves grow strong and luxuriant Like fluorescent lamps, some metal halide lamps are designed to give plants extra light sources beyond the red spectrum Although plants that grow only under HPS look unhealthy, they are actually good in some ways Because high pressure sodium lamps have high light energy in the red and orange parts of the spectrum, they can promote flowering and fruit, which is crucial for vegetables and flowers However, it is possible for the plant to become pale and taller and thinner than plants grown in sunlight or other light sources One of the main uses of high pressure sodium lamp is to make up light in greenhouse with enough blue spectrum.