These orchids are prized for
their long-lasting sprays of flowers, used
especially as cut flowers or for corsages in the
spring. There are two main types of cymbidiums --
standards and miniatures. Where summer nights are
warm (above 70 F), only miniatures can be
recommended, because many are more tolerant of
heat and able to flower in warmer weather.
L I G H T is important for
growing cymbidiums. Coming from cool and bright
areas in Asia, they need high light but cool
temperatures. In many southern climates, high
summer temperatures, especially at night, may
prevent the plants from blooming. The maximum
amount of light possible, short of burning,
should be given to the plants. This means only
light shade during the middle of the day, or
about 20 percent shade. In cool areas (such as
coastal California), full sun is tolerated.
Leaves should be a medium to golden green in
color, not dark green.
T E M P E R A T U R E S are
another critical factor in flowering standard and
miniature cymbidiums. During the summer, standard
cymbidiums are usually grown outside in
semishade, where day temperatures should be 75 to
85 F (or more), but night temperatures in the
late summer to autumn (August to October) must be
50 to 60 F to initiate flower spikes. Optimum
temperatures in winter are 45 to 55 F at night
and 65 to 75 F during the day. When plants are in
bud, temperatures must be as constant as
possible, between 55 and 75 E Miniatures can
stand temperatures five to 10 degrees higher than
standards and still flower. Most cymbidiums can
tolerate light frosts and to survive, but this is
not recommended. Bring them inside when
temperatures dip to 40 E In mild climates, they
can be grown outside year round. A bright and
cool location inside is best for winter months.
W A T E R to provide a
constant supply of moisture to cymbidiums, which
are semi-terrestrial plants. They generally
produce all their vegetative growth during the a
spring and summer and need the most water during
that period. Water heavily during the growth
season, keeping the potting material evenly
moist. Reduce water when the pseudobulbs complete
growing in late summer. Keep barely moist during
the winter.
H U M I D I T Y outdoors is
usually sufficient during the summer, except in
dry climates, where evaporative cooling in a
greenhouse is necessary. Keep humidity at 40 to
60 percent during the winter, especially if
plants are in bud. Keep the air moving to prevent
fungus (Botrytis) from spotting the
flowers.
F E R T I L I Z E at the
proper time to help cymbidiums flower. During the
growth season (spring through late summer),
high-nitrogen fertilizer (such as 30-10-10) is
used. In late summer, use a high-phosphorus,
blossom-booster fertilizer (such as 10-30-20), to
help form bloom spikes. Fertilize at full
strength every week to two weeks. In winter,
fertilize once a month.
P O T T I N G is usually done
in the spring after flowering, usually every two
years or when the potting medium decomposes.
Shake all of the old potting mix off the roots,
dividing the plant if desired. Pick a
water-retentive potting mix; medium-grade fir
bark with peat moss and perlite is a common mix.
Select a pot that will allow for at least two to
three years of pseudobulb growth before crowding
the pot, while planning on placing the active
growing pseudobulb(s) of the division farthest
from the side of the pot. Spread the roots over a
cone of the mix in the bottom of the pot and fill
the container with medium, working it among the
roots, tamping firmly. Single backbulbs need not
even be placed in mix until new growth and roots
are noted. Keep shaded and warm until new growth
sprouts, and pot as above.
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