Deficit irrigation is a crucial agricultural practice as irrigated agriculture becomes increasingly common in areas with limited water supplies. Deficit irrigation in arid regions can be effectively managed with the use of hydrogels. This study aimed at studying the effect of the hydrogel application rate on crop growth characteristics and soil properties under different irrigation levels and soil texture classes. Lettuce was used in this study, as a crop highly sensitive to water stress. Pot experiments were conducted using four irrigation levels (100%, 85%, 70%, and 60% of full irrigation requirements), four hydrogel application rates (0%, 0.1%, 0.2%, and 0.3%, expressed as a weight-by-weight percentage relative to soil dry mass) and three soil textures (clay, loamy sand, and sandy-clay soil). The crop growth parameters were significantly improved due to hydrogel application. Hydrogel significantly increased lettuce marketable yield, root fresh and dry weights, root diameter, and plant height. The hydrogel application of 0.3% and 85% of irrigation requirements did not result in significant yield reductions. The data also revealed that hydrogel application reduced soil salinity; the decrease was significant at high levels of hydrogel application (0.2% and 0.3% w/w). Under severe water deficit (60% of irrigation requirements), a hydrogel application rate of 0.3% significantly reduced soil salinity by 9.1% as compared to the control. These findings point out that hydrogel could be recommended to enhance crop growth and productivity under deficit irrigation and mitigate soil salinity risks associated with limited water conditions.