PubMed · 2026-03-24
Growing hydroponic lettuce at low salt concentration (EC 1.5–2.0 dS/m) combined with high light intensity (240 µmol/m²/s) maximizes leaf area and yield, while high salt levels drastically cut yields by over 75% regardless of lighting.
Low-salt + high-light treatment (EC1L3) produced the highest yield at 57.97 g per plant and leaf area of 1,338 cm², compared to just 13.98 g and 331 cm² under high-salt + high-light — a 77% yield reduction from excess salt.
Within the same low-salt conditions, increasing light intensity from 145 to 240 µmol/m²/s boosted yield by 47%, showing light is a powerful lever when salt stress is absent.
High salt levels suppressed uptake of all 11 measured nutrients (N, P, K, Ca, Mg, S, B, Zn, Mn, Fe, Cu), while light intensity had no significant effect on nutrient absorption except a minor interaction with boron.
