Problems With Orchids
Orchids can live in cultivation for many years - up to 100 years in established botanical gardens, for
example. But for this to happen, growing conditions have to be right
and any problems must be dealt with promptly. Over time, orchids progress in peaks and valleys. They advance toward a peak,
producing optimum growth and flowers. Then they may regress and take some
time before achieving another high performance crest. By recognizing
these progressions in your orchids, you will be able to encourage them to
grow and flower for years to come.
Problems with blooms
Non-flowering pseudo bulbs
- Plants are healthy, producing foliage from new pseudo bulbs, but no flower spikes.
Affects cymbidiums and other orchids that have pseudo bulbs.
- Each year, the pseudo bulbs on an orchid should become larger until the
maximum size is reached. By this time, the orchid will be of flowering size and
a flower spike will be produced. If the pseudo bulbs are getting smaller, the
orchids will not flower. The reason for this may be that too many of the older
pseudo bulbs have shed their foliage.
- Repot the orchid and at the same time remove the older, leafless pseudo
bulbs to restore the balance of the orchid. With fewer pseudo bulbs to support,
the orchid can grow forward again. When larger pseudo bulbs are produced, flower
spikes will follow.
Non-flowering, other types
- Orchids are healthy, producing plenty of foliage but no flower spikes.
- Cool-growing orchids. These may not flower if the
too high. They will then produce lush growth and no flowers.
Warmer-growing orchids. If these are grown in conditions that are too
warm, they will have dark green, limp foliage and no flowers.
- Cool-growing orchids. Move orchids to cooler surroundings. In time,
they should start to flower again.
Warmer-growing orchids. Phalaenopsis may need a
2-3 week period of cooler nighttime temperatures to initiate flowering. Only do
this when a healthy plant has not produced the expected flower spike for several
- All of the buds that have been developing normally on the flowering spike
turn yellow and drop off, just as they are about to open.
- The causes of bud blast can include overwatering,
cold and wet conditions, or, at the other extreme, surroundings that are too
warm and dry. A stuffy, poorly ventilated atmosphere will also cause buds to
- Try to maintain the correct growing conditions for your orchids. If the
orchid is ready to flower, do not change the conditions by, for instance,
bringing it indoors from a greenhouse or moving it
around the room. Instead, wait until the flowers are fully open before moving
- Flowers wilt prematurely, even though orchid blooms can be expected to last
for several weeks.
- The reason for flower-wilt can often be overheating or over dryness.
Flower-wilt often occurs in recently purchased orchids that have been left in
their cellophane wrappers for too long before being sold.
- Prevention rather than cure is the answer. Choose only healthy orchids when
buying, and remove an orchid from any wrapping as soon as you get it home. Pay
careful attention to the growing conditions needed for different orchids, and
try to provide an environment as close as possible to the ideal.
- This is most often seen on cymbidium orchids,
where the flowers have either become aged or have lost their pollen. The lips turn red and the flower dies.
- Pollen can be dislodged due to rough handling. On orchids outdoors, it may
be eaten by mice or pecked off by small birds. Once the pollen has been
removed, the flower dies. If the pollen has already turned black, it has rotted,
and the bloom will soon wither and die.
- Handle orchids carefully to avoid damaging them. Outdoors, prevention is the
only cure - try to make sure that the orchids are not vulnerable to raiding
- Blooms will often become spotted as they age, but spotting that occurs while
the flowers are still fresh is caused by a fungal disease
called botrytis. It is most often seen on cattleya
and phalaenopsis flowers.
- Cold and damp conditions or a lack of ventilation will encourage the
development of the fungus. It is most common in winter when temperatures are
- Destroy infected flowers and isolate any plants that are infected so that
the fungus does not spread. Give the careful attention to the conditions in
which your orchids are growing. Increase the air flow around the orchids and
reduce humidity to help to prevent the incidence
Problems with foliage
- Black or brown markings or spots form on the leaves. The tips of the leaves
can also be affected. The black starts at the tip and runs down the leaf.
- Sometimes spotted leaves do not indicate a problem. When they are old,
leaves may develop spots before turning yellow and being discarded by the plant
in the natural cycle of growth. Black tips that appear on older leaves are part
of the aging process. If young leaves have black tips, this is most probably
caused by overwatering or by nighttime temperatures that are too low.
- Sometimes the infection can be stopped by cutting off the diseased part of
the leaf. Check the roots to see whether the plant has been over watered. Repot
if necessary, or increase the temperatures. If the cause is the fungal
infection, an anti-fungal spray may help. To prevent the problem from recurring,
be sure to collect fallen leaves and dispose of them immediately.
- Black or black-edged patches on leaves can indicate sunburn. The leaves of
some of the Odontoglossum purebred hybrids can
become red during the summer.
- Black patches occur when the sun has shone directly on a portion of leaf for
too long; it takes less than an hour for the sun to burn the leaves. A little
redness in odontoglossums is acceptable, but if they receive too much sun, the
leaves will suffer and be prematurely shed.
- Once burned, the mark will remain. Prevent sunburn by sheltering plants from
the sun. particularly in spring, when the plants are still in their winter
quarters and the sun is becoming increasingly bright.
- Rot that affects pseudo bulbs can be dry or wet. When an older bulb at the
back of a plant shrivels and turns brown, it is drying naturally. Where root
occurs in one or all of the newer pseudo bulbs, affected pseudo bulbs will turn
brown and wet. This rot starts at the base of a pseudo bulb and will run through
the plant. Cattleya orchids and miltoniopsis
orchids are particularly susceptible.
- Rot in new pseudo bulbs is caused by overwatering or by the plant remaining
in a sodden state for a long time. Rot can also start in the new growth if water
has lodged among the leaves and remained there for some time.
- Cut away the affected pseudo bulbs to save the front part of the orchid. Do
this by cutting through the rhizome, discarding the
diseased part of the plant, and dipping the remaining portion in a fungicide
solution. Allow the plant to dry completely before potting it in a smaller pot.
Treat wet rot in leaves by dusting the affected part with powdered sulfur.
- A virus infection often appears in young leaves as white streaking, either
parallel to the vein or showing a defined diamond pattern along the length of
the leaf. On broad-leaved orchids, such as phalaenopsis and cattleyas, a virus
appears as black pitting on the leaf. As the foliage ages, the damaged areas
turn completely black, the result of a secondary infection coming into the leaf
to survive in the dead leaf cells. The blackened areas are often the first
noticeable sign of leaf-cell damage, and within a short time the virus will
spread through the whole plant.
- Botanists believe that viruses are present in all plants, but only manifest
themselves when a plant is weakened and not growing strongly. Orchids with a
virus infection are usually unhealthy before the virus strikes, so they are
under stress and less able to resist attack.
- The only remedy is to discard the plant before the virus spreads to other
- From time to time, the oldest leaves on a plant will turn yellow and drop
off. This is a natural process. Where all the leaves take on a yellow shade of
green, a nitrogen deficiency may be present.
- Nitrogen deficiency can be the result of insufficient nutrients in the
compost. It may be old and used up or have decomposed. The problem can also be
caused by not feeding the plant enough while it was growing. Exposure to too
much light also causes overall yellowing of the foliage.
This seldom occurs indoors and is more likely to happen when orchids are grown
in a greenhouse with inadequate shading. Cymbidium
orchids placed outdoors for the summer can also turn yellow if they are left in
too bright position.
- Repot if new compost is necessary, and allow the orchid to establish a new
root system before applying a nitrogen-based feed at regular intervals of every
second or third watering. While waiting for new roots
to develop, give a regular foliar feed once every two weeks, misting the foliage
so that minute water droplets cover the leaves like dew. This will return the
foliage to a healthy green.
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