An experiment was conducted at Horticultural Research Station, Pechiparai, Tamil Nadu Agricultural University during the year 2017-2018 to standardize the media for hardening the plantlets of Dendrobium var. Thongchai Gold. The in vitro plantlets were hardened with four different growing media and their combinations viz., charcoal, coconut husk, broken pot pieces, thermocol and their combinations as charcoal + coconut husk (1:1) , charcoal + broken pot pieces (1:1), charcoal + thermocol (1:1), coconut husk + broken pot pieces (1:1), coconut husk + thermocol (1:1), charcoal + coconut husk + broken pot pieces (1:1:1) and charcoal + coconut husk + broken pot pieces + thermocol (1:1:1:1). The results revealed that combination of coconut husk and broken pot pieces in 1:1 ratio significantly enhanced the plant height (9.02 cm) and number of leaves per plantlet (4.61) while the control recorded the plant height of (7.47 cm) with 3.50 leaves per plant. The leaf length (6.96 cm), root length (6.90 cm) and shoot girth (3.20 mm) were the highest in the treatment combination of coconut husk and broken pot pieces in 1:1 ratio. In the control the leaf length (5.52 cm), root length (5.30 cm) and shoot girth (2.20 mm) respectively. The highest survival per cent of 83.49 was recorded in the same treatment where as the survival per cent in the control was 62.55. Hence it can be concluded that the treatment combination of coconut husk and broken pot pieces in 1:1 ratio was the best medium for hardening the in vitro plantlets of Dendrobium var. Thongchai Gold.