Greenhouse Tomato Lighting: Can LED Light Replace High Pressure Sodium Lamp?

In February 2020, as a national high-tech enterprise, Plusrite electric (China) Co., Ltd.

became the first batch of enterprises to  resume production. A new round of plant lighting 

research has been   launched in the glass greenhouse of Plusrite. The theme of this round 

of experiment is whether LED light can replace high-pressure sodium lamp for auxiliary lighting 

of greenhouse crop reproduction system,  and the planting object is infinite growth cherry tomato.

First of all, we simulated the light distribution of greenhouse lamps by a professional software. 

According to the simulation results,the double ended 1000W high-pressure sodium lamp and led top 

light module for tomato light supplement developed by Plusrite are installed in the glass greenhouse.

Under the two kinds of supplementary lights,the plants canopy level at the same height can achieve the 

same photon flux density (PPFD). Each lighting system is installed in a common greenhouse environment to 

ensure that all light treatments have the  same environmental conditions. At the same time, no light 

compensation area is set as blank control. High pressure sodium lamp fill light,led fill light, no fill 

light three test areas are separated by lightcurtain to ensure that the light does not affect each other.

We measured the growth status of tomato plants (leaf number, height, stem diameter, canopy size, etc.) every week. 

By the middle of April 2020, through observation and data analysis, tomato plant morphology in light supplement area 

and no light supplement area had a significant difference, and the light supplement area was significantly better than 

the non light supplement area. However, although there are differences in plant morphology between high pressure sodium 

lamp and led two different light supplement test areas,the difference is not significant, we are still tracking. We hope 

that when the experiment finish, we can provide more possibilities for tomato supplementary light scheme according to the 

experimental data analysis results.

         In the final stage of the experiment, we will evaluate the plant morphology, plant biomass, fruit yield and quality of Tomato in greenhouse. 

In the whole experiment process, we continuously recorded the canopy level PPFD, the energy consumption of high pressure sodium lamp and 

led under each treatment, and will calculate and compare the energy use efficiency at last, and research whether LED light can replace high 

pressure sodium lamp under certain conditions to achieve the purpose of energy saving and improving plant characteristics.