The effects of irrigation timing on growth, yield, and physiological traits of hydroponic lettuce

Crop-specific timing of irrigation is necessary to conserve irrigation water and improve yield of vegetables. Therefore, the experiment was conducted to identify the optimum irrigation timings for hydroponic lettuce plants. Three nutrient solution timings, T1(once a day at 0900 hours), T2(once on alternative days at 0900 hours), and T3(once at two-day intervals), and three varieties, ‘Legacy’ (V1), ‘Red fire’ (V2), and ‘Green wave’ (V3) were evaluated. Growth and yield parameters, including number of leaves, leaf length, leaf diameter, and fresh weight of leaves, and growth parameters, including leaf area (LA), leaf area ratio (LAR), leaf mass ratio (LMR), root weight ratio (RWR), relative growth rate (RGR), and net assimilation rate (NAR) were determined. The values of growth parameters were the highest for T1. The highest and lowest NAR and RGR values were obtained for T1 and T3, respectively. The values of most growth traits, including fresh weight, NAR, and RGR were higher for V1 than other varieties. T1 provides high yield with comparatively less irrigation water and nutrient solution so it can be used to culture lettuce using aggregate hydroponics as.