Extended life span, improved flower qualities, and enhanced water use efficiency of potted Curcuma cv. ‘Jasmine Pink’ under off-season production by low R:FR light provided by incandescent as night break techniques

• Night break (NB) lighting with a low red to far-red (R:FR) ratio promoted off-season flowering in potted Curcuma . • NB with low R:FR enhanced vegetative growth and flower quality, although it delayed flowering time. • NB lighting improved water use efficiency and maintained physiological stability under limited irrigation. • Improved WUE under NB lighting with a low R:FR ratio contributes to future strategies for off-season Curcuma production and efficient irrigation scheduling. We successfully produced Curcuma spp. as an off-season potted plant by using a supplemented lighting technique night break (NB), which likely inducing physiological changes, including alterations in water consumption. This experiment investigated the phenology, growth, water use, and photosynthetic parameters of Curcuma cv. ‘Jasmine Pink’ under off-season conditions. Plants were grown under plastic nursery cover for 45 days before being divided into two groups: NL (natural short daylength; 11.4 ± 0.5 h), and NB (natural light plus 2 h of low red to far-red (R:FR) ratio incandescent light from 20:00 to 22:00). Plant under NB conditions exhibited extended vegetative growth and significantly enhanced traits, including number of leaves, plant height, shoots, flowers, total dry weight, rhizome development, number of storage roots, and compactness index (CI), compared to NL plants. The longer lifespan and increased aerial biomass in NB plant resulted in a 19.14 % increase in total water consumption relative to NL. Nevertheless, NB plants showed significantly lower transpiration rate (E) and stomatal conductance (Gs) per leaf area, resulting in improved intrinsic water use efficiency (WUEi). Notably, no significant different in net photosynthetic rate (Pn) was observed between groups during daytime measurements. This study highlights the effectiveness of a low R:FR night break lighting approach in promoting off-season flowering in ornamental Curcuma . It also provides a basis for future water management strategies in potted cultivation.