<p>Black ginger (<i>Kaempferia parviflora</i> Wall. ex Baker) is an important medicinal herb from the Zingiberaceae family. However, studies on water management for this crop are limited. The objective of this investigation was to evaluate growth characteristics, rhizome yield, water productivity, and physio-biochemical traits of black ginger under different irrigation regimes using a Red-Green-Blue (RGB) plant morphometrics of high-throughput phenotyping platform. Five irrigation treatments based on different levels of field capacity (FC) were applied: 125% FC (I₁₂₅), 100% FC (I₁₀₀), 75% FC (I₇₅), 50% FC (I₅₀), and 25% FC (I₂₅). Restricted irrigation at I₅₀ and I₂₅ led to slow growth and growth retardation, as revealed by plant morphometric parameters. At harvest, rhizome dry weight was the highest under I₁₀₀, but decreased by 54% and 92% under I₅₀ and I₂₅, respectively, compared with I₁₀₀. The maximum water productivity (1.43&#xa0;kg&#xa0;m⁻³) was observed under I₇₅. Flavonoid yield in the rhizome also declined under I₅₀ and I₂₅ compared with I₁₀₀. Leaf greenness and photon yield of photosystem II were the highest under I₇₅, reaching 35.78 SPAD units and 0.81, respectively. Conversely, photosynthetic abilities, such as leaf greenness, photon yield of photosystem II, net photosynthetic rate, stomatal conductance, and transpiration rate, were significantly reduced under I₂₅, leading to elevated leaf temperature and crop water stress index. Overall, the results revealed that I₇₅ is an optimal irrigation regime for black ginger, which can be recommended for its field-scale production. The current study was limited by the pot culture using a modified substrate and growing under environmentally controlled greenhouse. The present results, especially the data on water requirements of black ginger, need to be further validated under field conditions with different climatic environments.</p> Graphical abstract <p></p>