Root-zone Temperature Effects on Pepper

Ten-week-old pepper plants (Capsicum annuum L. ‘Bell Boy’) were grown at 5 different root-zone temperatures (RZT) (12°, 18°, 24°, 30°, or 36° ± 2°C) for a period of 8 weeks. Maximum shoot dry weight and leaf area were measured at 24° and 30° RZT. Leaf area ratio (LAR) was not significantly affected by RZT treatments. Fruit weight was maximum at 30° RZT, but earliness was delayed at high RZT. Nitrogen, P, and K content of shoots were increased, but Mg and Ca concentrations were reduced at high RZT. Plant photosynthesis was the highest at 36° RZT. Increasing RZT improved both greenhouse or outdoor pepper production.