According to the natural law of plant growth and the principle that plants use grow light for photosynthesis, the plant grow light is a tool that uses light instead of sunlight to provide the light source needed for plant growth and development.
The needs for supplementary light：
(1)When the light intensity is lower than its compensation point, the consumption of organic matter is more than the accumulation, and the dry weight of the plant decreases, or even dies. Even under the condition of weak light, the growth of the plant is weak and appears to be overgrown.
(2)Affect flowering and fruiting. Solanaceous fruits and melons have certain requirements for light duration and intensity. If the light duration of watermelon is less than 11 hours, all young fruits will fall off.
According to the summary of research and production practice, we generally divide the disaster into three levels.
(1)Light level: no sunshine for 3 consecutive days; Or there is no sunshine for 3 of the 4 consecutive overcast days, when cucumber, tomato, pepper and other epidemics and downy mildew begin to appear.
(2) Intermediate: no sunshine for 4-7 consecutive days; Or the sunshine duration is less than 3 h for more than 7 consecutive days; Or there are two times of low light level in one month. At this time, diseases such as cucumber, tomato and pepper are common, but they can be controlled through chemical control and other measures.
(3) Severity: ≥ 8 consecutive cloudy days; Or sunshine hours<3 h for more than 10 consecutive days; Or in January, there were two times of intermediate low lighting, at this time, 10% – 20% of the disease was difficult to control, most of the yield was reduced, and continued to develop.
Therefore, light is closely related to crop growth. Maximizing the capture of light energy and giving full play to the potential of plant photosynthesis will directly affect the benefits of plant growth and crop production. Therefore, in recent years, LED plant grow light has developed rapidly, mainly composed of red and blue LED beads, and pink light of LED red and blue combination. LED plant grow light, which is suitable for ecological garden and household indoor plant grow light needs.