Optimized substrate selection for enhanced orchid growth based on high-throughput lysimetric arrays

Orchids are highly valued ornamental plants whose growth conditions directly impact the economic returns of the horticultural industry. The substrate, acting both as a physical support and a nutrient reservoir, is critical for orchid development. Therefore, the careful selection of an appropriate growth substrate is of paramount importance. However, existing research on the relationship between orchid growth and substrate properties relies mainly on manual measurements of physiological indicators, with limited application of high-throughput phenotyping (HTP) platforms. In this study, we evaluated three distinct substrate types, peat soil mixed with perlite, pine bark, and river sand, which were applied to two orchid species, Cymbidium goeringii and Cymbidium faberi. Using the high-throughput Plantarray lysimetric system, we continuously recorded environmental parameters (photosynthetically active radiation, humidity, and temperature) as well as key growth metrics (biomass accumulation, canopy conductance, and transpiration rate). This platform enabled precise and rapid quantification of orchid growth indicators. The results show that the type of substrate significantly affects orchid growth. Under controlled conditions, mixed substrates that provide balanced nutrition and excellent drainage enhanced orchid growth compared to other substrates. Additionally, when the data obtained from the HTP platform were compared with those from traditional manual measurements, the automated system showed higher reliability and accuracy. This study not only provides practical guidance for selecting cultivation substrates for orchids, but also establishes a robust scientific framework for integrating advanced phenotyping technologies into orchid cultivation practices.