Freshwater alternatives to irrigate crops are in dire need of time because of changing climate and scarcity of freshwater. Therefore, seawater can be the best feasible option as it is abundantly available on Earth. Sole application of seawater for agricultural crops is impossible, but the blend with freshwater may not be aggravating the salinization problems in soils. The present investigation was conducted to evaluate the possibility of growing the short period summer vegetables i.e., eggplants, tomato, and pepper with fresh and seawater blends viz. 5%, 10% and 20%, termed as A, B and C treatments, respectively. During the experiment, we considered: (i) crop growth, biomass yield, water consumption, water use efficiency (WUE) and water productivity (WP); (ii) photosynthetic pigments and gas exchange parameters; (iii) concentration of mineral contents and quality traits; (iv) lipid peroxidation, proline contents and ascorbic acid. Tomato productivity was markedly decreased by application of B and C treatments, whereas the growth of eggplant and pepper were not much influenced at the same concentrations. Water consumption dropped, whereas WUE significantly increased in all tested crops upon increasing seawater concentrations. Leaf Na+ concentration and other mineral elements increased. These results assumed that certain concentrations of seawater–freshwater blends revealed that there were no significant effects on the quality characteristics, mineral elements concentration and productivity of eggplant and pepper plants; however, tomato plants indicated sensitivity at the three seawater concentrations (A, B and C SFW treatments). Moreover, low concentrations of salinity stress (5% and 10% SFW) seemed to be necessary to attain better crop nutrition and organoleptic values. Accordingly, the results of present will be helpful to coastline farmers in cultivating vegetables and produce nutritive food for their family.