What do orchid aerial roots do?
In Phalaenopsis orchids, thick aerial roots outside the pot absorb water, exchange gases and provide anchorage.
Structure, development and life cycle
A spongy multilayered tissue called velamen rapidly absorbs water and protects the inner root from brief drying. Chlorophyll in inner tissues may look green when wet. In nature roots cling to bark; the orchid is not parasitic but uses the tree as support. Healthy roots outside a pot should not be cut merely for appearance.
Growing, uses and cautions
Airy orchid bark, bright indirect light and watering when roots turn silvery are suitable. Do not leave the pot in water or the leaf crown wet for long. Flower-spike pruning depends on plant condition and whether the spike remains alive. Room-temperature water is preferable to ice cubes, which may cold-shock tropical roots.