Impact of Water Temperature on Seedling Quality Parameters in Lactuca sativa L., Solanum lycopersicum L., and Brassica oleracea var. gongylodes L.

Heat stress represents a significant challenge to global agricultural production, with particular emphasis on air temperature stress. Despite considerable attention to this issue, limited information is available regarding the impact of irrigation water temperature on the quality of vegetable crops. In this study, kohlrabi, tomato, and lettuce were subjected to three distinct irrigation temperatures: 17 °C, 24 °C, and 34 °C. A variety of parameters were measured for the three vegetables, including seedling height, relative chlorophyll content (SPAD), mass of the green part (FW), mass of roots (FW), dry weight (DW) of the green part, DW of roots, and leaf area. The results indicated a significant decrease in oxygen (O2) content with rising water temperature, with a 20.8% reduction at 34 °C compared to 17 °C. Notably, the highest temperature of 34 °C exerted the most positive influence on the studied parameters, particularly evident in kohlrabi and tomato. This study addresses a critical knowledge gap by elucidating the impact of irrigation water temperature on the growth and development of vegetable seedlings. The findings presented here lay the groundwork for further investigations into the effects of heat stress on agricultural practices.