Application of wide-spectrum light-emitting diodes in the indoor production of cucumber and tomato seedlings

Horticulture is now revolutionized by advancements in light-emitting diode (LED) lighting. New technologies enable knowledge expansion on how plants require different spectral illumination for optimal growth and development. The aim of this study was to evaluate the quality of cucumber (Cucumis sativus L. ‘Parys F1’) and tomato (Solanum lycopersicum L. ‘Poranek’) seedlings produced in indoor controlled conditions, using three different types of LED tubes emitting warm light (AP67, AP673L, and G2). The photosynthetic photon flux density was set at 50–65 µmol m−2 s−1 and a 16-hour light regime was used. The results were compared to the cool daylight-emitting fluorescent (FL) control (tube lamp TLD 36W/54). A detailed analysis of the biometrical parameters of the aboveground and underground parts of seedlings was performed. Moreover, the content of chlorophyll in the leaves was measured. No effect of light spectra on the underground part of cucumber was found. On the other hand, the type of lamp affected the number of leaves and chlorophyll content in this species. Lamps AP673L and FL can be recommended in the production of cucumber seedlings. The obtained seedling had characteristics desired for horticultural production, i.e., compact habit with a fair number of leaves and chlorophyll content. As for tomato, the FL lamp had the best effect on the development of seedlings. Due to the high share of far red light, the tested LEDs stimulated the elongated growth of flaccid plants, unsuitable for commercial producers. Our findings not only described the effect of various light spectra on plant development but can also be useful for producers of popular vegetable crops.