GROWING ORCHIDS UNDER
There are two types of orchids which will grow
well, year round, under artificial lights:
phalaenopsis (known as the moth orchid) and
paphiopedilums (known as the lady slippers).
There are other orchids which will bloom under
windowsill and/or artificial light conditions, but
these orchids require more light than do phals and
The minimum set-up for the use of fluorescent
bulbs is two 40 watt tubes. A practical set-up
would alternate Gro-lux or Vita-Lite wide spectrum
lights with cool white fluorescent tubes.
The lights may be left on up to 16 hours a day.
Because fluorescent light produces no heat, they
should be within 12" of the plants.
The optimum light for phalaenopsis is between
1000 to 1500 footcandles. Paphiopedilums, which
require less light than most orchids, thrive at 800
to 1200 footcandles of light. An easy- to-use light
meter should be used to measure the amount of
Bob Gordon, a noted author of culture books on
phalaenopsis offers the following advice on the use
of fluorescent light: "For phalaenopsis culture
under artificial lighting with fluorescent tubes,
use a fixture(s) with four of what used to be
called 40 watt, 4 foot tubes. Replace the tubes May
1 and lower the tubes to 4 inches from the leaves
of the plants. On October 1, replace the tubes
again and lower the fixtures to about 2 inches from
the leaves. The date of October 1 to replace the
tubes is not arbitrary; it is chosen to kick off
the flower induction process...which happens
because the tubes put out a 25% or so excess above
their rated capacity for a month or so during the
lamp's burn-in period...just right to initiate
flower induction. If a mature, healthy phal does
not flower in its season, the reason is very likely
lack of light, either in intensity or duration.
Under lights, vary the duration from 8 hours on
December 21st to 12 hours on June 21st in the
Northern Hemisphere. The 2 to 4 inches will handle
the needed intensity."
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