Lettuce is a cool-season leafy green commonly grown in hydroponics. Romaine lettuce is economically expensive, yet it has more desirable health benefits and market demand than other lettuce types. However, high electrical conductivity (> 2.0 dS m −1 ) of water impacts nutrient supply and growth, thus affecting its economic viability. Despite negative impact of salt stress on hydroponically grown lettuce, its effects on the pla...