Abstract
A study was conducted with lettuce plant. Three varieties (Tom Thumb, Paris Island and Ice Queen) were grown for 2 seasons in hydroponic experiment. The electrical conductivity of nutrient solution was maintained at values 1.0, 1.5 and 1.8 mmhos/cm, respectively. Fresh weight and mineral composition (N, P, K, Zn, Mn, Fe and Cu) were investigated. Fresh weight production of the three lettuce varieties decreased with increasing EC level of the nutrient solution. The mineral composition of lettuce plants was influenced with different EC levels and the varieties used. This study suggested that Paris Island is the best variety in terms of quality and quantity production under hydroponic system.