2017 ASHS Annual Conference

Historically, orchids have been associated with the wealthy and orchid enthusiasts, but today Phalaenopsis orchids are readily available to all consumers due to the advancements in production, breeding, and propagation. Proper irrigation is a challenge faced by consumers, but plant care instructions can alleviate the problems of over or under watering. Ice cube irrigation is a method promoted to give structured, straight forward instructions for irrigating orchids. Chilling or freezing damage caused by the ice is a concern because Phalaenopsis orchids are native to tropical regions. The objective of this study was to evaluate the health and display life of Phalaenopsis orchids irrigated with ice or room temperature water. The experiment was conducted at The Ohio State University (Wooster, OH) and University of Georgia (Athens, GA). At each location, 24 orchids (6 plants of 4 different cultivars) were irrigated with three ice cubes and 24 orchids were irrigated with the equivalent volume of room temperature water every week. The longevity of an individual flower and the overall display life of the whole plant were determined. Plants were maintained in an interior evaluation room for 4 to 6 months, until the last flower on the plant senesced. Leachate volumes were measured to determine how much water was used by the plant or held by the bark growing media. The chlorophyll content of the leaves, quantum yield of photosystem II of the leaves and roots, and final dry weights of the leaves and roots were used to monitor the effect of ice irrigation on the health of the plants. The temperature in the media was also monitored during irrigation events. Flower longevity and display life were the same in ice and water irrigated plants of all cultivars. The efficiency of photosystem II and chlorophyll content also showed no treatment effect. The leachate volume after ice irrigation was equivalent or lower than the leachate volume after water irrigation. Leaf and root dry weights showed similar results between the two irrigation methods. The temperature of the bark after ice irrigation reached a low of 11˚C. Ice irrigation did not cause early flower loss or damage the plant’s photosynthetic health, while providing a sufficient amount of water to the orchid. A consumer’s success with their potted plants is an important aspect of the industry, and irrigating with ice should be considered a viable irrigation option for Phalaenopsis orchids in bark media.