For the Best Blooming of your Cymbidiums, keep them outdoors or in a place which is cool at night (40-55F is ideal and they are tolerant down to freezing) until the first flower opens. In temperatures that are too warm, buds may drop. If the location has bright filtered light, the flower color will be brighter. As the flowers begin to open, you can display the plant where you like.
While cymbidiums may be considered
temperature tolerant - withstanding limits of 27 to
100°F - most require periods of cooling in order to
bloom. With the exception of some heat-tolerant
miniatures, flower-spikes are
initiated in autumn when the differential between
day and night temperatures plays a key role.
Indoor conditions or climates that stay
persistently warm without cooling off at night
(below 55°F in winter) are not suited for
blooming standard cymbidiums. The ideal temperature
range for cymbidiums is 40 to 90°F. During heat spells, it is
essential to boost the humidity by watering and misting more frequently.
During cold spells, cymbidiums can take 32°F but should be given
some protection in case the temperature drops further. Damage to
spikes will occur at 27°F and to the plant at 25°F. To guard against
effects of the cold, plants should be moved up against the house or
under a tree. If plants must be brought indoors, they should be brought
into a bright location with night temperatures below 55°F. Warmer
night temperatures for any prolonged period can cause developing buds
to turn yellow and drop off; however, once flowers have opened, they
no longer require the cool and may be brought indoors for show.
Light is the most important factor in
attaining good cymbidium
culture. Mature cymbidiums need bright
filtered light (55% shade) all day or full
morning sun. Without proper light you
will see weak growth and no flowers.
Good light also brings out the best in cymbidium
colors; shady conditions result in greener, muddier-colored blooms.
Watch the color of the leaves; foliage should be yellowish-green in
color, but too much light will result in a pale yellow color. Burning will
cause a black spot at the arch of the leaf, or if severely burned, the leaf
will be bleached white. If too shady, plants will be
dark, lush green but will bloom less or not at all.
When watering a cymbidium, water thoroughly, and then allow the mix
to almost dry out before watering again. We recommend running copious
amounts of water through; first to wet the mix and then again for the
roots to drink up. Thorough watering also helps prevent salt build-up,
which can result in tip-burn (browning on the tips of the leaves). Plants
should be grown in a well-draining medium and should never be left sitting
in water, which can lead to root or bulb-rot. One way to tell when
to water is to judge by the weight of the pot; the pot will be heavy as
long as there is plenty of moisture; light when it is dry. This may be an
average of once a week depending on climate, plant size, and the condition
of the mix; water more frequently in periods of dry heat and winds
and less in cold, wet weather; finer mediums will hold more moisture
and need less watering than courser mediums, which tend to dry out
faster; large, overgrown plants will take more watering than younger
disivions or seedlings.
Fertilizer should be provided throughout the year since the potting medium
provides none. The most convenient method is to apply a timerelease
fertilizer such as Osmocote 18-6-12 once a year, at one tablespoon
per gallon of pot size. Alternatively, a water soluble
fertilizer such as 7-9-5 DynaGro or Peter’s 20-20-20 at 1/2 strength can
be used along with regular watering.
The ideal time to repot is after flowers have
finished blooming and the new growth is just
starting (late spring for most varieties), if and when
the potting medium has broken down or the plant
has grown over the sides of the pot. Typically this
is every 3 to 4 years. If the plant has room to grow
(even if crowded) and the mix is in good condition, leave it. Plants may
either be divided (to make more, smaller plants) or kept together and
potted up into larger tubs (to make a multi-spike specimen).
First, take the plant out of the pot and remove the old bark. Cut away
any dead or compacted roots from the bottom of the root-ball. Always
sterilize cutting tools between plants. If you decide to divide the plant,
look for natural divisions which allow three to five-bulb groupings. If
the dormant bulbs (back bulbs) can be removed without destroying the
strength of the division, remove them. These can be potted separately to
resprout and bloom in two to four years. Select a pot size which will
allow the plant to grow unrestrained for three to four years. Usually,
two inches between the plant and the side of the pot is
sufficient. When placing the plant in the pot, position the bulbs so they
sit just a little into the surface of the medium and so that the newest
growth is in the center of the pot, with room to grow. Plants should be
potted firmly by pouring the medium around the roots while tapping the
sides of the pot and pushing down on the top with thumbs or a potting
stick. We use fir bark or coconut chips (1/8 to 1/4 inch size) as a potting
medium - not soil or potting mixes that hold too much water and don’t
allow good air movement around the roots. If you are in the area, come
see us for a potting demonstration!