Effect of light quality (LQ) and lighting method (LM) on canopy area on day 21 (CA21), total leaf area (LA), biomass per unit area (BMA), and shoot dry weight (SDW) in green romaine lettuce.

Least-square means with standard error of the model (in parenthesis) are shown in the table. Statistical significance of the main and interaction effects of the fitted model is shown below the table. The symbols ‘*’ and ‘**’, indicate P values ≤ 0.05 and 0.005, respectively, and ‘n.s.’ indicates no statistical significance. The least-square means with a different letter are statistically different (Tukey-Kramer procedure).