Major losses of fresh tomatoes happen during post-harvest storage due to prompt senescence and diseases. The aim of the research was to evaluate the effects of different spectra of LED lights on the post-harvest preservation of ascorbic acid, lycopene, and total soluble solids, the weight and size of tomato fruits, as well as to determine the optimal exposure time and distance of irradiation and extension of shelf-life. Therefore, experiments were carried out in a climate chamber with shelves equipped with three different light spectra: red light-emitting diodes, red–blue–white light-emitting diodes, and ultraviolet-light-emitting diodes. Light treatment had a certain positive effect on the firmness, size, and mass of samples. Thus, tomato fruits (Panekra) exposed to the spectra of LED lights demonstrated a better quality of firmness and mass compared to the control samples (non-preserved) of tomatoes. The treatments with RL significantly improved the concentration of lycopene than FL and UV-LED lights, although the highest concentration of lycopene was observed in the control samples for the first 7 days of the storage. After 21 days, the ascorbic acid content in the red spectrum was found to be much higher than in the other two spectra and control samples, coming in at about 1.8 mg/100 mL compared to 1.0 mg/100 mL for the control samples. Total soluble solids also increased significantly after preservation, rising from 3.9 °Brix in the control samples to roughly 7.3 °Brix in samples preserved using the full spectrum after 21 days. Overall, the results of the study demonstrated that tomato preservation using the investigated techniques induced lycopene concentration, ascorbic acid, and total soluble solids concentrations. The results derived from this study provide highly useful information in the field of post-harvest preservation.

Light qualities are considered to affect many plant physiological processes during growth and development. To investigate how light qualities make an influence on tomato seedlings under greenhouse conditions, the growth and morphological parameters of tomato seedlings (Fortizia F1RC hybrid) were studied under three supplemental light irradiations such as light-emitting diodes with nanoparticle coating (LED 1—Red light-emitting diodes); Blue, Green, Yellow, Red light-emitting diodes (LED 2), and traditional high-pressure sodium (HPS) lamps with different photosynthetic photon flux density and the same irradiation time for 33 days. Morphological appearances of three groups of tomato seedlings were different between light treatments, that is, the plants under LED-1 and LED-2 were shorter than those under HPS, while stem diameter, leaf area, dry and fresh weights, and health indices of tomato seedlings grown under alternative light sources were higher than of those cultivated under traditional HPS lights. However, the higher plant height was in plants containing traditional high-pressure sodium lamps treatment. Photosynthetic pigments were shown to have a significant difference under respective light irradiations of LEDs. The levels of photosynthetic pigments were higher in the leaves of seedlings under LED 1 and LED 2, and lower in those that underwent HPS control treatment. Based on the data of morphological and statistical analysis, LEDs with nanoparticle coating proved to be beneficial factors for the growth of tomato seedlings under greenhouse conditions.