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Cattleya
Cattleyas are among the most
popular orchids. Their culture
is often used as the basis for
comparison with other types of
orchids. Cattleyas and their
related hybrids come in many
colors, shapes, forms and
sizes. Culture varies only
slightly among most of these.
This sheet is a general guide to
basic cattleya culture. Like
many other cultivated orchids,
cattleyas are epiphytes, or air
plants. They have developed
water-storage organs, called
pseudobulbs, and have large,
fleshy roots covered with a
spongy, water-retentive velamen.
They are accustomed to being dry
at the roots between waterings,
and therefore should be potted
in free-draining media.
Light is the
most important factor in growing
and flowering cattleyas, whether
in a greenhouse or in the home.
Bright light to some sun should
be given to the plants, with no
direct sun in the middle of the
day. This means an east,
shaded-south (as with a sheer
curtain) or west window in the
home, and 50 to 70 percent full
sun in a greenhouse (3,000 to
5,000 foot-candles). Leaves
should be a medium-green color,
pseudobulbs erect and requiring
no staking.
Temperatures
should be 55 to 60 F at night
and 70 to 85 F during the day.
Seedlings should have night
temperatures five to 10 degrees
higher. A 15- to 20 degree
differential between day and
night is recommended, especially
for mature plants. Higher day
temperatures can be tolerated
(up to 95 F), if humidity, air
circulation and shading are
increased.
Water should be
provided in two ways: in the pot
by watering and in the air as
humidity. Watering in the
container is dictated by many
criteria: size and type of the
vessel, temperature, light,
etc. Mature cattleyas need to
dry out thoroughly before being
watered again. Seedlings need
more constant moisture. Compare
the weight of a dry pot of the
same size and type of mix; it
can indicate if a plant needs
water by the relative weight -
light means dry, heavy means
wet. If in doubt, it's best to
wait a day or two until
watering. Plants in active
growth need more water than
plants that are resting. Water
below 50 F may injure plants, as
will water softened by the
addition of salts.
Fertilize on a
regular schedule. In fir bark,
a high-nitrogen (such as
30-10-10) formulation, or a
similar proportion, is used.
Otherwise, use a balanced
fertilizer. When in active
growth, plants need fertilizer
at least every two weeks, and
when not actively growing, once
a month. Fertilizer can also be
applied with every watering at
one-quarter the recommended
dilution. Thorough flushing
with clear water every month is
recommended to prevent the
buildup of fertilizer salts.
Potting is
necessary when the rhizome of
the plants protrudes over the
edge of the pot or the potting
medium starts to break down and
drain poorly (usually after two
to three years). It is best to
repot just before new roots
sprout from the rhizome, after
flowering or in the spring.
Mature cattleyas are usually
potted in coarser potting
material than are seedlings.
Until a plant has at least six
mature pseudobulbs, it generally
should be put into a larger pot
and not divided. If dividing a
plant, three to five psuedobulbs
per division are required.
Select a pot that will allow for
approximately two years of
growth before crowding the pot.
Pile mix against one side of the
pot and cut off any dead roots.
Spread firm, live roots over the
pile, with the cut rhizome
against the side of the pot.
Fill the pot with medium,
working around the roots. Pack
firmly and stake if necessary.
Keep the plant humid, shaded and
dry at the roots until new root
growth is seen.
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