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Paphiopedilum


Paphiopedilums, or slipper orchids, originate from the jungles
of the Far East and Indonesia. They are semi-terrestrial,
growing in humus and other material on the forest floor, on
cliffs in pockets and occasionally in trees. They're easy to
grow in the home, under lights or in the greenhouse.


LIGHT is easier to provide for "paphs", as we will call them,
than many other types of orchids. They like shady conditions,
as in the home in an east or west window, or near a shaded
south window. In the greenhouse, heavy shade must be provided -
- giving them about 1,000 to 1,500 foot-candles. They are often
grown under the bench, provided precautions are taken to
prevent rot. Fluorescent light is excellent; use 2 or 4 tubes
just over the leaves.


TEMPERATURES for paphs range considerably. Many growers
separate paphs into two groups, the warmgrowing mottled-leaf
types and the cool-growing, green-leaf types. Warm-growing
types should be 60 to 65 degrees F at night and 75 to 80
degrees F or more during the day. Cool-growing types should be
50 to 60 degrees F at night, 75 to 80 degrees F during the day.
Many growers grow all plants in the same temperature range with
excellent results. The plants can stand night temperatures in
the 40's if necessary (as when grown outside in mild climates),
as well as temperatures to 95 degrees F. Care must be taken to
protect the plants from rot when cold (keep humidity low, and
do not let water stand on leaves or in the crowns of the
plants), and also to protect from burning when hot (shade more
heavily and increase humidity and air movement).


WATER must be available at the plant's roots constantly, since
they have no pseudobulbs, and therefore store most of their
water in their leaves. They need a moist medium -- never soggy,
but never dry. Water once or twice a week. Humidity for paphs
should be moderate, between 40% and 50%, which can be
maintained in the home by setting the plants on trays of
gravel, partially filled with water, so that the plants never
sit in water. In dry climates, misting (in the morning only)
can help increase humidity. In a green house, average humidity
is sufficient; spraying the floor or using an evaporative
cooling system in warm climates can increase the humidity. Air
movement is essential, especially when humidity is high.


FERTILIZER must be applied on a regular schedule, but care must
be taken to avoid burning of the fleshy, hairy roots. High-
nitrogen fertilizers (like 30-10-10) are recommended when
potted in any fir bark mix. In warm weather, some growers use
half-strength applications every two weeks; others use 1/4
strength every watering. It's important to flush with clear
water monthly to leach excess fertilizer, which can burn roots.
In cool weather, fertilizer applications once a month are
sufficient.


POTTING should be done about every two years, or as the medium
decomposes. Seedlings are often repotted annually. Mixes vary
tremendously; most are fine- and/or medium-grade fir bark, with
varying additives -- perlite (sponge-rock), coarse sand,
sphagnum moss, etc. Moisture retention with excellent drainage
is needed. Divide large plants by pulling or cutting the fans
of the leaves apart, into clumps of 3 to 5 growths. Smaller
divisions will grow, but may not bloom as well. Spread the
roots over a small amount of medium in the bottom of the pot
and fill with medium, so that the junction of roots and stem is
buried 1/2" deep in the center of the pot. Do not overpot; an
average plant should have a 4 to 6" pot.


Prepared by: Education Committee, American Orchid Society
6000 S. Olive Ave., West Palm Beach, FL 33405 (407) 585-8666.

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