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Does ice cube irrigation damage Phalaenopsis orchids?

Irrigating potted Phalaenopsis orchids weekly with ice cubes has been recommended as a simple solution to help consumers avoid both under- and overwatering. The theory is that ice cubes provide a convenient way to apply a set volume of water, which is released slowly as the ice melts through the porous bark media, allowing more water to be absorbed by the bark and roots and resulting in less water accumulation in the bottom of pots where it may cause root damage.

ICE-CUBES-1Irrigating potted Phalaenopsis orchids weekly with ice cubes has been recommended as a simple solution to help consumers avoid both under- and overwatering.But concerns were raised about whether the ice cubes would cause low temperature damage to the plants. So, a research study was conducted to reveal the effect of this method on flower longevity and display life, according to a news release.

The September 2017 issue of HortScience published joint research by members of Ohio State University’s Department of Horticulture and Crop Science and the University of Georgia’s Department of Horticulture on the effects of ice cube irrigation on Phalaenopsis orchids. Research treatment methods included either weekly application of three ice cubes or the equivalent volume of room-temperature tap water.

Monthly measurements determined the volume of leachate in the outer decorative pots after irrigation and also the orchid bark growing media temperature during irrigation was recorded. The quantum yield of photosystem II in roots and leaves was evaluated monthly to determine if photosynthetic efficiency was affected by the ice irrigation.

The results? “In general, the leachate volume over time was the same or lower in ice-irrigated orchids compared with those irrigated with the same volume of water. Ice cube irrigation did not damage the orchid roots or photosystem II. No premature flower loss or abnormal flower development was observed in either the ice or water treatment.”

The experiments confirmed that there were no detrimental effects on the quality or display life of potted Phalaenopsis orchids growing in bark, demonstrating that ice cubes are a viable method of irrigating these tropical houseplants.

So, advising your customers to use weekly ice cubes for watering their orchids appears to be a good idea. The research proved that “consistent irrigation in the form of three ice cubes per week, rather than a measured volume of water, is a simpler, more convenient technique for consumers. The slower release of water from ice cubes can allow for an increased uptake of water by the plant or greater retention within the media.”