Supplemental artificial light in greenhouses is fundamental to achieving sustainable crop production with high yield and quality. This study’s purpose was to investigate the efficacy of supplemental light (SL) sources on the vegetative and reproductive growth of cherry tomatoes. Four types of light sources were applied, including high-pressure sodium lamps (HPS), a narrow-spectrum LED light (NSL), and two specific full-spectrum LED lights (SFL1 and SFL2) with a shorter blue peak wavelength (436 nm) and/or green peak wavelength (526 nm). The control was the natural light condition. Shoot fresh and dry weight and leaf area in the SFL1 and SFL2 treatments were greater than those in the control. The HPS and NSL treatments also enhanced tomato growth, but they were less efficient compared to the SFL treatments. The SFL1 and SFL2 treatments showed higher fruit yields by 73.1% and 70.7%, respectively, than the control. The SL sources did not affect the effective photochemical quantum yield of photosystem II (Y (II)). However, they did trigger the increased electron transport rate (ETR) and non-photochemical quenching (NPQ). The SFL treatments enhanced tomato growth, fruit yield, and efficient use of light and energy, suggesting that the specific full spectrum based on the short-wavelength blue and/or green peak can be successfully applied for the cultivation of cherry tomato and other crops in greenhouses.

Light is essential for plant production and has various effects on plant quality. Vertical farms typically use light-emitting diodes (LEDs) as light sources. However, the cost of LEDs varies with wattage and the initial installation costs are generally high. Therefore, to explore more cost-effective LED designs, we aimed to investigate the impact of red LED chips density on light distribution and plant growth under the same total electricity consumption. To this end, we exposed baby leaf soybean (Glycine max (L.) Merr.; 5 days) and kale (Brassica oleracea var. acephala; 18 days) to LEDs light with different arrangements of red and white chips. Plants were exposed to either 2 W chips with a red: white ratio of 4: 64 (2W4R treatment) or 1 W chips with a red: white ratio of 8: 64 (1W8R treatment) across the entire LED bar. We observed that the distribution of red light in the cultivation room differed depending on the density of the red LED chips. We found that arranging low-power red LED chips at narrow intervals resulted in uniform light distribution across the entire cultivation bed, positively affecting crop growth. Baby leaf soybean and kale exhibited uniform growth under 1W8R and growth was particularly enhanced in kale. This may be because of the dense leaf structure of kale, which promotes photosynthesis under a uniform light environment. The results of this study demonstrate that a favorable light environment can be created by altering the position and distribution of red LED chips, thereby inducing uniform growth in plants.