In mass production of seed-potato plantlets, the processes for in vitro propagation and ex vitro acclimatization with a high cost should be improved by a culture system with environmental control using scaled-up culture vessels. The experiment was conducted to design a hydroponic culture system for enhancement of growth and development of seed-potato (Solanum tuberosum) plantlets cultured under photoautotrophic (without sugar in culture medium) conditions with controlled light intensity and ventilation rate. The culture system was consisted of scaled-up culture vessels, ventilation pipes, a multi-cell tray and an environmental control system (ECS) for optimum controlling in temperature, light intensity, ventilation rate, and culture-medium supply. Growth and development of the plantlets was significantly increased under the ECS compared with a conventional culture system (CCS) of photomixotrophic culture (with sugar in culture medium) using small scale vessels. For 21 days, leaf area of the plantlets was expanded more than 2 times, and number of internodes also approximately 4 times greate. under the ECS. In addition, the photoautotrophic growth in sweetpotato (Ipomoea batatas) and chrysanthemum (Chrysanthemum morifolium) plantlets was greater more than 2 times compared with the CCS.