L I G H T 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.
W A T E R 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.
H U M I D I T Y should be 50 to 80 percent for cattleyas. This can be provided in the home by placing the plants
on trays of gravel, only partially filled with water so that the plants do not sit in the water. Air should always
be moving around the plants to prevent fungal or bacterial disease, especially if high humidity or cool temperatures
exist. In the greenhouse, the humidity is best increased by use of a humidifier. Evaporative cooling increases
humidity while cooling the air.
FERTILIZE on a regular schedule. In fir bark, a high-nitrogen (such as 30-1010) 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.
P O T T I N G 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 pseudobulbs 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 the firm, live
roots over the pile, with the cut rhizome against the side of the pot. Fill the pot with medium, working it 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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