                                Cymbidium

These orchids are prized for their sprays of large flowers, used especially as cut flowers
or for corsages m the springtime. There are two main types of cymbidiums - standards and
miniatures. Where summers are warm (above 90 degrees F), only miniatures are
recommended, because they are more heat-tolerant and bloom in warmer weather.

LIGHT is very important for growing cymbidiums. Coming from cool and bright areas in
Asia, they need high light but cool temperatures. In many of our climates, the high level 
of light cymbidiums need is accompanied by high temperatures in the summer, which may
cause the plants not to bloom. There are several ways to counteract this: spray the plants
with water during summer afternoons to cool the plants down, shade more heavily and
increase air movement. 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% shade. In cool areas (e.g., coastal California), full sun is tolerated. Leaves should be
a medium to golden green in color, not dark green.  Shade more in the winter, especially
if in bud.

TEMPERATURE is the most critical factor in blooming cymbidiums of either type.  During
the summer, standard cymbidiums are usually grown outside in semi-shade, where day
temperatures should be 75 to 85 degrees F (or more), but night temperatures in the late
summer to fall(August to October) must be 50 to 60 degrees F to initiate flower spikes.
Optimum temperatures in winter are 45 to 55 degrees F at night and 65 to 75 degrees F
during the day.  When in bud, temperatures must be as constant as possible, between 55
and 75 degrees F. Miniatures can stand temperatures 5 to 10 degrees higher than
standards and still bloom well.  Most cymbidiums can stand light frosts and survive, but it
is not recommended. Bring them inside when temperatures fall to 40 degrees F; in mild
climates they may be grown outside year-round. A bright and cool location inside is best
for winter months. 

WATER must be provided at all times to cymbidiums. As semi-terrestrials, they need a
fairly constant supply of moisture. Since they produce all their vegetative growth during the
spring and summer months, they need the most water then. Water heavily during the 
growth season, keeping the potting medium from drying out completely, and reduce water
when the pseudobulbs are completed in late summer.  Keep barely moist during the winter.

HUMIDITY outdoors is usually sufficient during the summer months, except in dry climates
where evaporative cooling in a greenhouse, or misting outside, is necessary. Keep
humidity at 40%-60% during the winter, especially if plants are in bud.  Keep the air moving
to prevent fungus (Botrytis) from spotting the flowers.

FERTILIZING at the proper time will help cymbidiums bloom.  During the growth season
(spring through late summer) high-nitrogen fertilizer (like 30-10-10) is used.  In late
summer, use a high-phosphorus, bloom-booster fertilizer (like 10-30-20), to help form
bloom spikes. Fertilize at full strength every week to two weeks. In winter, fertilize once a
month.

POTTING is usually done in the spring after blooming, usually every two years or when the
potting medium decomposes. Shake all the old potting mix off the roots, dividing the plant
if desired.  Divisions of green bulbs with leaves must have 3 to 4 bulbs minimum to bloom;
bulbs without leaves are considered backbulbs, and need special care to grow (see below). 
Pick a potting mix that will hold moisture well; a medium-grade fir bark with peat moss and
perlite is a common mix.  Select a pot that will allow for at least 2 to 3 years of pseudobulb
growth before crowding the pot, while planning on placing the active growing bulbs 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 pot with medium, working it among the roots, tamping firmly.
The junction of roots and pseudobulbs should be about 1/2" to 1" below the top of the mix. 
Keep shaded, drier at roots but humid, until new roots grow. Backbulbs may be left on the
division to add strength, or removed to propagate. Take single backbulbs, and bury
halfway in a bark or peat/sand mix.  Keep shaded and warm until new growth sprouts, and
pot as above. It may take up to three years to produce a blooming-size plant from this
method.