Spring is one of the busiest times
of the year for orchid growers. Many
genera are beginning their growth cycles with new leaves and roots,
while Spring Cattleyas and Phals are in full bloom.
In addition, those that have harbored their orchids in windowsills
and bathrooms are ready to move them outside and reclaim their living
space. Be careful not to shock your orchids with
sudden increases in light or dramatic changes in temperature. Spring may have sprung, but nights can still
be cold.
Phalaenopsis begin to put out new roots,
even while bearing flowers, when day length reaches 12 hours and temperatures
are warm. A decline in night
temperature caused by moving them outside or turning off the heat in
the greenhouse can induce Phals to stop growing and spike again. This can lead to long spikes with a few flowers,
with the corresponding cessation of growth. Summer blooming Phals exposed to cool conditions may abort both
flowering and growth as they come from climates that are warm all year
long.
Spring is an excellent time to repot
because most orchids are in a growth mode, quickly replacing roots lost
during repotting. Another reason
is that media can sour or degrade in winter when gloomy days and low
temperature allows media to stay wet and turn mushy.
This is especially true for soiless mixes and even for dense
media containing a high proportion of fine bark.
Paphs and Phals are especially susceptible as they do not like
to have their roots dry completely, so are more likely to be over watered. For these two genera, more frequent repotting is better than waiting
too long. Other genera typically
potted in course media that is allowed to dry thoroughly between watering
will usually grow out of the pot before requiring repotting.
Vandas are generally considered warm
growing, even though they tolerate cool conditions in winter. Their growth comes largely when temperature
is high and nights warm. If
they cool down too much each night, Vandas will often cease both root
growth and the production of new leaves.
Avoid prematurely placing them outside.
Wait until night temperature is 60 degrees F or higher.
Most of us leave flowers on plants
as long as possible for maximum enjoyment.
If, however, an orchid has been weakened by losing part of its
root system or by having dealt with disease or pests, removing flowers
early can enhance growth and perhaps the survival of the plant. Flowers will not last as long, but removing them will prevent a
tremendous drain of energy from the plant and lead to new growth. Each year mites cause damage, especially on
thin-leaved Dendrobiums and similar-leaved orchids in my collection.
By the time they are recognized in May the damage is done. This pest thrives on low humidity and can be
prevented simply by keeping humidity high.
If this is not feasible, a light spray of oil (Ultra-fine or
Sun-oil) on the leaf, especially the underside, will limit the damage. Be sure to apply oils (and all pesticides)
when leaves are cool. Leaves
should be dry before they are exposed to bright light.
This year several Phals in my collection
had cold water dripping into the crown each night, a sure way to develop
crown rot. Not a single case
developed on these or any other Phal in my collection during the past
growing season despite not using any fungicide or bactericide. The only cases occurred on three newly purchased
Phals. I have long believed
that genetically weak plants and plants that have deficiencies in certain
nutrients get rots. Avoiding
excess nitrogen fertilizer, excess micronutrients, and providing more
Potassium, Calcium, and Magnesium is the key.
If rots plague your Phal collection cut back on nitrogen and
phosphorous and grow a year. Your
plants will not grow as fast, but there will also be fewer rot problems.