Documents: Special Interest: Orchids:

Phalaenopsis or Moth Orchids
by Marilyn Light
March 27, 2005

Phalaenopsis or Moth Orchids are warm-growing orchids that sometimes struggle in out home environments. The temperature may not be warm enough, the air may be too dry or sometimes mineral salts accumulate in the growing medium such that roots cannot grow.

Small plantlets produced on Phalaenopsis inflorescences are called offsets or 'keikis' the latter name being Hawaiian for 'baby'. Keikis are miniatures of the same plant. Once they become sufficiently large to bloom, they will have identical flowers to the parent plant. Keikis are sometimes produced instead of flowers or when the parent plant is >stressed. Keikis should have developed one or two good roots before being severed from the plant. One way to encourage root development is to lay or pin the keiki to damp sphagnum moss and allow the roots to develop. Alternatively, a well-rooted keiki can be removed and potted separately. Use a sharp sterile blade to cut the stem. More keikis may form later from the same stem.

When Phalaenopsis plants refuse to grow, the problem may be that the temperature is a bit too cold to encourage growth. An alternative reason is that salts from tap water and/or fertilizer have accumulated in the potting medium and this inhibits root growth. To remedy the situation, remove a plant from its pot. Remove any soft, mushy roots which are obviously dead. Rinse the plant in deionized water or in rainwater. Place the plant in a transparent plastic bag together with some damp sphagnum moss then hang the loosely fastened bag in a warm spot out of direct sun. The bag could be placed beneath artificial lights. The important thing is that the plant is warm (22-25C) but not cooked! A change between day and night temperature is encouraged. In a warm, humid environment, a plant will quickly resume growth. The first sign will be a noticable plumping of the foliage followed by root tip growth. The bag may be opened occasionally to freshen the air. Once the plant breaks its self-imposed dormancy, it can be repotted in fresh medium. Water only with deionized water and very dilute fertilizer weekly until rooting is accomplished.


Copyright Marilyn H.S. Light

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