9.1 Cultural problems common to most orchids
9.1.1 Leaves
9.1.2 Leaves or new growth
9.1.3 Buds, flowers & flower spikes
9.1.4 Roots
9.1.1 Leaves
9.1.2 Leaves or new growth
9.1.3 Buds, flowers & flower spikes
9.1.4 Roots
9.5 Oncidiums and intergenerics with Oncidiums
9.5.1 New growth, leaves
9.5.2 Flower spike, buds & flowers
9.5.1 New growth, leaves
9.5.2 Flower spike, buds & flowers
Leaves are dark green, look very healthy,
but plant does not bloom:
Probably due to insufficient light.
Check your light level, move the to within one to one and
a half feet of a bright, unobstructed windowsill (window
exposure depends on type of orchid).
Leaves are not as lustrous, eventually
they shrivel:
plant is not absorbing enough water. Check
the root system. If roots are abundant, look healthy, are firm
and are white, then the plant is being underwatered. If
the root system does not appear healthy repot as soon as
possible.
Yellowing of leaves = chlorosis.
May be due to excessive light and/or
deficiency in nitrogen.
Clear or watery spots on leaves:
usually result from bacterial infection.
Repot plant, treat plant with a fungicide, keep it on the
dry side for a few weeks.
Discolored area on top of curled leaves or
on leaf area exposed to light:
most probably due to sunburn or excessive
light for this type of orchid.
Pitting on new foliage:
tissue collapse due to use of too
cold water or because of too cold temperatures.
Tips of leaves are burned (black), roots
are withered:
plant is overfertilized or burned by
fertilizer. Check your fertilizer dosage, make sure you water
thoroughly with plain water once a month, make sure you do not
water with fertilizer when the plant is completely dried out.
Leaves turn yellow, then brown and die:
probably due to fungi, as a result of
excessive watering/soggy or decaying potting mix and/or
excessive humidity possibly combined with too cool
temperatures. Unpot the plant, treat it with a fungicide,
cut dead / brown growth and leaves, repot in fresh potting mix.
Allow the plant to dry in between waterings.
Black streaks on leaves :
may be caused by a number of cultural
problems or by a virus. If due to a virus, this will
eventually show up on all growths. Newly developed growth may
at first appear normal, but eventually they will display same
symptoms. If this a plant you particularly like, you may have
it tested for virus. Plants
can not be cured from viruses, and
viruses may be transmitted to your other plants through
insects, water splashing from plant to plant, or from grooming
without sterilizing instruments. If the plant has a
virus, it’s best to dispose of it.
Soft, rapid growth:
may be due to excessive nitrogen
New growths are smaller, not as plump than
previous ones, are stunted, do not grow upright:
the plant is under stress, either because
of weakened root system or
insufficient light or too extreme
temperatures, deficiency in nitrogen, or a combination of
these. Check light, temperature levels & fertilizer dosage.
Repot if needed.
Buds yellow and drop:
extreme temperatures, extreme or
insufficient light, drafts, too dry air, inadequate watering,
micronutrients deficiency or excesses or weak root system.
Flowers do not open up fully:
may be due to genetics, or by too low
temperatures, or may be due to too low humidity or thrip
damage.
Flowers are too small, colors are not as
strong as before:
most probably due to insufficient light,
and or too extreme temperatures.
Flowers fade too fast:
may be caused by too high or too low
temperatures, exposure to direct sunlight, exposure to drafts,
too low humidity, fertilizing or micronutrients deficiency,
inadequate watering or poor condition of the root system.
Too few flowers:
weak plant, too low light, phosphorous
deficiency.
Brown streaks or mosaic patterns on
flowers:
may be due to a virus.
Poor display of flowers:
When buds start to form on the flower
spikes, be careful not to change the orientation of the flower
spike (which leans toward the source of light) so as to get the
best possible display of flowers.
Are black or brown:
may be damaged (broken) or have rotted
(root rot fungus). Cut damaged & rotten roots.
If rotted, treat with a fungicide, repot plant, keep a
little drier.
Chewed or missing tips:
chewed by pests (millipedes, sowbugs,
snails or slugs).
Dead tips:
may be caused by salt built-up due to too
hard water or excess fertilizer or not leaching medium
regularly.
Deformed:
may be due to chlorine deficiency.
Stunted roots:
probably because of micronutrients
deficiency.
New leaves are smaller than previous ones: the plant is under stress, either because of
weakened root system or insufficient light or too extreme
temperatures or a combination of these. Check light and
temperature levels. Repot the plant if needed.
Crinkled leaves:
may be due to insufficient watering.
Limp, dull, eventually wrinkled leaves: the plant is not absorbing enough water,
either because of a poor root system or because of inadequate
watering. Check root system, repot, water as required.
Reddish leaves:
is often normal on the underside of leaves. On the upper side
it may be due to excessive light, or deficiency in nitrogen
and/or deficiency in phosphorous.
Red coloration on new foliage: may indicate a fungus. Treat with a
fungicide.
Reddish or discolored bottom leaves: bottom leaves are dying back. May be normal
when new leaves are formed. Mature plants carry from 4 to 6
leaves, and replace 1 or 2 per year. May be also a result
of repotting shock, especially if newly repotted plants are not
misted and if they are subject to too high light.
No or limited new leaves: often result from nitrogen and/or phosphorous
deficiency.
Leaf loss: if
it is not due to aging while new leaves are being produced, is
an indication of stress which may result from extremes in
temperatures, humidity, watering or phosphorous deficiency.
Treat plant with a fungicide/germicide, repot in sphagnum
moss, keep at very high humidity (enclose in plastic bag?).
This will probably not revive the plant but is may induce
it to produce keikis.
Flower spike is crooked or discolored:
may be due to a virus. Isolate
plants until final diagnosis.
Limp spikes:
may be normal for some species and
resulting hybrids, otherwise indicates too low light.
Too short flower spikes:
usually due to excessive light.
Spikes turn brown at the tip:
were subjected to too cold water, resulting
in collapsing tissue.
Spike develops keikis:
normal for some species, but can be cause
by too high temperatures, insufficient light, decaying potting
medium, plant in poor health.
Thin flower spikes:
may be due to phosphorous deficiency or too
low light.
Flowers rot or are spotted:
caused by fungi if water is allowed to
stagnate on them or because of excessive moisture/humidity.
You can help the plant by cutting the
flower stem after flowers have faded. Removing the spike
after flowers have faded will induce plant to generate more and
larger flowers at its next blooming season.
Plants getting right conditions will spike
more or less naturally in late fall or winter or early spring.
You can induce flowering by subjecting plants to 2 or 3
weeks of night temperatures in the mid to low 60’s.
Flower spikes should appear about six weeks later.
Growth turns brown, then dies:
probably due to fungi, as a result of
excessive watering/soggy or decaying potting mix and/or
excessive humidity possibly combined with too cool
temperatures. Unpot the plant, treat it with a fungicide,
cut dead / brown growth and leaves, repot in fresh potting mix.
Allow the plant to dry in between waterings.
No or limited new growth:
may result from nitrogen and/or phosphorous
deficiency, or damage / rotting of growth buds (at basis of
previous growth).
Sheath dries out:
may be because plant was immature (1st
attempt at blooming) or may be species related as some
Cattleyas will bloom after the sheath has dried out.
Sheath and/or buds turns brown and are
watery:
water stagnated in/on the sheath and
provoked sheath and probably buds) to rot. Gently open
sheath to check if buds are still green. If yes,
completely open sheath to expose buds . If buds are yellow or
brown, remove sheath & buds. In either case make sure water
does not gather and stagnate there.
New growths are smaller, not as plump than
previous ones, are stunted, do not grow upright: the plant is under stress, either because of
weakened root system or insufficient light or too extreme
temperatures, deficiency in nitrogen, or a combination of
these. Repot the plant, check light, temperature levels,
fertilizer dosage,....
Leaves turn yellow and die:
probably due to insufficient watering
Growth turns brown, then dies:
probably due to fungi, as a result of
excessive watering/soggy or decaying potting mix and/or
excessive humidity possibly combined with too cool
temperatures. Unpot the plant, treat it with a fungicide,
cut dead / brown growth and leaves, repot in fresh potting mix.
Allow the plant to dry in between waterings.
No or limited new growth:
may result from nitrogen and/or phosphorous
deficiency, or damage / rotting of growth buds (at basis of
previous growth), or poor root system, but often due to poor
repotting or overdue repotting.
Sheath and/or buds turns brown and are
watery:
water stagnated in/on the sheath and
provoked sheath and probably buds) to rot. Gently open
sheath to check if buds are still green. If yes,
completely open sheath to expose buds . If buds are yellow or
brown, remove sheath & buds. In either case make sure water
does not gather and stagnate there.
Buds dry and drop:
Bud drop may occur if day or night
temperatures are too high. Ideally when buds start to
develop (usually in fall or winter), day temperature should not
go much above 65 F and night temperatures should, if possible,
be maintained between 50 F and 60 F.
Flowers yellow and drop:
extreme temperatures, extreme or
insufficient light, drafts, too dry air, inadequate watering,
micronutrients deficiency or excesses.
New growths are smaller, not as plump than
previous ones, are stunted, do not grow upright:
the plant is under stress, either because
of weakened root system or insufficient light or too extreme
temperatures, deficiency in nitrogen, or new growth growing
over the edge of the pot, or new growth too high up (and roots
not taking hold in the medium), or a combination of these.
Repot the plant, check light, temperature levels, fertilizer
dosage,....
Leaves turn yellow, then brown and die:
probably due to fungi, as a result of
excessive watering/soggy or decaying potting mix and/or
excessive humidity possibly combined with too cool
temperatures. Unpot the plant, treat it with a fungicide,
cut dead / brown growth and leaves, repot in fresh potting mix.
Allow the plant to dry in between waterings.
Growth turns brown:
same as above.
No or limited new growth:
may result from nitrogen and/or phosphorous
deficiency, or damage / rotting of growth buds (at basis of
previous growth).
Flower stem dries out and does not develop:
probably due to insect damage, plant not
absorbing enough water or temperatures out of range (i.e. too
low day time, too high night time).
Flower stem turns brown and is watery:
water stagnated in/on the flower stem and
provoked flower stem and probably buds) to rot. Remove
flower stem, make sure water does not gather and stagnate
there.
New growths are smaller, are stunted, do
not grow upright:
the plant is under stress, either because
of weakened root system or insufficient light or too extreme
temperatures, deficiency in nitrogen, or a combination of
these. Repot the plant, check light, temperature levels,
fertilizer dosage,....
Leggy plants growing tall:
may indicate plants are not receiving
sufficient light (they are stretching themselves to reach the
light).
Tips of leaves are brown or spotted:
plant is not absorbing enough water either
because of insufficient watering or because of root rot.
Leaves turn yellow, then brown and die:
probably due to fungi, as a result of
excessive watering/soggy or decaying potting mix and/or
excessive humidity possibly combined with too cool
temperatures. Unpot the plant, treat it with a fungicide,
cut dead / brown growth and leaves, repot in fresh potting mix.
Allow the plant to dry in between watering.
Watery spots on leaves that turn brown or
gray or black, sometimes with yellow on the margins:
usually result from bacterial infection.
Repot plant, treat plant with a fungicide, keep it on the
dry side for a few weeks.
White spots and/or irregular dark patches:
may also result from bacterial infection.
Treat as above.
No or limited new growth:
may result from nitrogen and/or phosphorous
deficiency, or damage / rotting of growth buds (at basis of
previous growth), or setback if the plant was divided and left
with only one growth.
Note: If
plants or portions of plants are infected by bacteria, take immediate action
as the infection can spread rapidly
and kill the plant. Unpot the
plant, remove all affected area, treat with a
fungicide/bactericide, repot in fresh media.
A Comprehensive Guide to orchid Culture
Venamy Orchids
1460 Route 22
Brewster, New York10509
1460 Route 22
Brewster, New York10509
Toll Free
1-800-362-3612
1-800-362-3612
Fax
(845) 279-2682
(845) 279-2682
venamy@orchidsusa.com
Copyright 2002
Venamy Orchids
Venamy Orchids