1

Culture Characteristics for Phalaenopsis

The beautiful orchids, Phalaenopsis pot plant, have had the highest price among

the ornament plants for a long time. However, because of over-supply, the price

decreased sharply in 2008. Plants with low quality have been driven out the market.

Only high quality orchids are of benefit. This paper discusses the basic techniques to

produce high quality Phalaenopsis.

1. Special characteristics of organs of Phalaenopsis

The important organs for Phalaenopsis are the roots, leaves and spikes.

1.1. Roots

The functions of roots include fixing the plant in the substrate and absorbing

water and nutrients. The root contains chlorophyll, so the natural color is green. Roots

have the ability for photosynthesis and assimilation. The adequate environment for

roots is moist (vapour) and not soaked with water.

The nutrients dissolved in water cannot be adsorbed by roots directly. The

nutrients are adsorbed with the vapour in the air. The adequate substrates for

Phalaenopsis must be able to provide moisture, fresh air (oxygen) and nutrients.

If the pot material is transparent, light can pass through the pot wall and provide

the energy of photosynthesis. Healthy roots are green and bright.

1.2. Leaves

The most important organ for Phalaenopsis is leaves. Leaves have the

photosynthesis ability for carbon fixation and the assimilation function to store the

available carbon. Except of Ca and Mg, nutrients can be adsorbed into leaves directly.

The required carbon sources for spikes and flowers are provided from leaves.

2

1.3. Spikes

The natural color for spikes is green. Spikes contain chlorophyll and have the

same photosynthesis ability same as for leaves and roots. However, the assimilation

materials are not sufficient for development of spikes and blossoms. So the required

dry matter for spikes and blossoms is provided by leaves.

The priority of dry matter distribution for Phalaenopsis differs from that of other

plants. Roots are the first to obtain dry matter. The ranking of dry matter distribution

is roots＞leaves＞spikes＞blossoms.

2. Coexistence of vegetable and reproductive phase

Most orchids have vegetative and reproductive stages. The plants at the vegetative

stage are in the state of growing and developing, and plants at the reproductive stage

are in the state of spiking and flowering. The distinction between the two stages is so

obvious for many orchids. Oncidium is a typical orchids. At the vegetative stage, the

dry matter is produced and stored in pseudobulbs. At the reproductive stage, the

leaves stop the photosynthesis function, and the required nutrients of spikes and

blossoms are taken from pseudobulbs.

Phalaenopsis has special characteristics for vegetative and reproductive stages.

Plants developing from tissue culture plantlets to reach the mature stage, they are in

the vegetative stage. As these mature plants are moved to a cooling environment for

spiking, they are in the reproductive stage until the length of spike reaches to 3-5 cm.

However, two stages coexist in the flowering phase. The spikes are lengthened

continuously and buds appeared (reproductive stage). The leaves accumulate dry

matter and send it to spikes and blossoms (vegetative stage); that is, the required dry

matter of spikes and blossoms are taken from leaves. The leaves need to supply the

dry matter to spikes and blossoms in the flowering stage.

The microclimate control and fertilization work are important at the flowering

3

stage. The leaves must be maintained at optimal day and night temperature. The light

intensity and period are also important. The nutrients need to be supplied correctly. So

the leaves must accumulate enough dry matter and send it to spikes and flowers to

ensure flower quality.

3. Factors affecting Phalaenopsis quality

3.1. Genotype

The genotype characteristics of the Phalaenopsis variety include flower color,

pattern, flower size, flower number, numbers of spike, multi or no branches, and stem

height, etc.

3.2. Healthy conditions

The plant must mature enough before cooling. Enough dry matter must be stored

in plants. The plants must be protected against disease, pest damage, viruses, chemical

damage and salt accumulation in substrate.

4

Figure 1. These plants are in good conditions for cooling treatment

3.3. Environment

The environmental factors, such as day temperature, night temperature, relative

humidity, light period and intensity must be kept at the optimal range.

The interaction of genotype, health conditions and environment needs to be

emphasized. The genotype decides the maximum possible expression for flower quality.

For example, the orchids with little white flowers, P. amabilis, containd genes for more

twenty flowers. If the plant is mature enough and the cooling environment is appropriate,

the grower can obtain more than twenty flowers for each plant. However, the number of

flowers will decrease if the plant is immature, or has been damaged by disease or pests, or

if the temperature or light intensity are not maintained well.

The effect of microclimate on other flower qualities is described below:

3.2.1. Temperature difference in vegetative and cooling stages

The numbers of spikes is affected significantly by the temperature difference between

the vegetative and cooling phases. The "Mansanfong" variety is used to illustrate the effect

of temperature difference on number of spikes. The adequate day and night temperature for

the vegetative stage is 28℃and 26℃, respectively. If the cooling temperature of day and

night is kept at 25℃and 20℃, 100％ these plants have one spike. As the cooling

temperature of day and night is maintained at 23℃ and 20℃, 40％ of these plants have

spikes and 60％ of these plants have one spike. At the environment of 20℃ day

temperature and 18℃ night temperature, 100% of these plants have two spikes.

3.2.2. Difference between day and night temperature at flowering stage

The symbol DT represents the difference between day and night temperature at the

flowering stage. With increasing DT, the length of spikes (or stems) is lengthened. With

5

decreasing DT, the length of spikes (or stems) is shortened.

Figure 2. DT increase, the length of spikes is too long

3.2.3. Day temperature at flowering stage

If the day temperature at the flowering stage is the same or higher than that of the

vegetative stage, a leaf will appear in the stem. It is called as “Keiki’s”. Despite the

day temperature not being higher than the temperature of vegetative stage, it is still

higher than the normal condition and the high day temperature will reduce the flower

quality. The position of the first bud is heightened, all buds will be blocked up in the

end of stem, the flower color will fade and the number of branches is decreased.

6

Figure 3. Keiki’s of the Phalaenopsis

Figure 4. All buds will be blocked up in the end of stem because the day

temperature is too high

7

3.2.4. Night temperature at the flowering stage

If the night temperature at the flowering stage is higher than the adequate

condition, the number of blossoms is decreased and the flower size is reduced.

4. Diversity characteristics of Phalaenopsis varieties

The required qualities are two or more spikes, multi-branching, bright color, and

40-to 75-cm height in The Netherlands. According to the Culture Guide of

Floricultura b.v., the adequate environment conditions for Phalaenopsis are as

follows:

Table 1. Adequate environment conditions for Phalaenopsis

Day temp Night temp Light intensity

Vegetative phase 28℃ 26℃ 4000-6000lux

Cooling 20℃ 18℃ 7000-8000 lux

Flowering phase 23℃ 20℃ 7000-8000 lux

However, the growers usually find that many varieties cannot produce the

required quality according to these environment conditions.

In the orchids greenhouse, the leaf colour of some varieties turned red and dark

(Figure 5) in The Netherlands. Some varieties are still induced to spike at the growing

regions (day temp. 28℃, night temp. 26℃) (Figure 6). Some varieties cannot induce

any spikes at the cooling regions (day temp. 20℃, night temp.18℃) (Figure 7).The

reason for these results can be explained by the diversity of Phalaenopsis varieties.

8

Figure 5. Leaves colour of different varieties was found that turned into red and

dark at the same light level

9

Figure 6. Some varieties still be induced to spike at the growing regions

(day temp. 28℃, night temp. 26℃)

Figure 7. Some varieties can not be induced any spikes at the cooling regions

(day temp. 20℃, night temp.18℃)

5. Classification of Phalaenopsis characteristics

5.1.According to the culture temperature

Seven types of Phalaenopsis varieties are classified by optimal day and night

temperature for the vegetative stage:

A. 31-33℃ / 25-26℃, such as V3, P. Sogo Yukidian

B. 28-30℃ / 24-25℃, such as P. amabilis

C. 28-30℃ / 21-22℃, such as D. Queen Beer

D. 24-25℃ / 20-21℃, such as P. Taipei Gold

E. 21-22℃ / 18-19℃, such as P. Fortune Saltzman

10

F. 26-31℃ / 21-24℃, such as D. Sin-Yuan Golden Beauty

5.2.According to light intensity

The required light intensity of the Phalaenopsis is influenced by the growing stage.

The required light intensity of mature plants is usually higher than that of small size

plants. A typical variety of big white flowers, V3, P. Sogo Yukidian is used to

illustrate the levels of light intensity at different stages.

Table 2. The required light intensity at different stages for P. Sogo Yukidian

4.0 '' pot 25000 lux

3.0 '' pot 18000 lux

2.0 '' pot 10000 lux

flask 5000 lux

The effects of environment on the flower quality are presented by the following

case.

The beautiful blossom of three spikes is shown in Figure 8. This variety is grown

at Pingtung County, southern Taiwan. High day and night temperature (32℃/26℃)

and high light intensity (25000 lux) was provided. Then plants were sent to the

cooling room (day and night temperature 23℃ /18℃, light intensity 28000 lux).

When the healthy and mature plants were placed in cooling rooms, three spikes were

induced. Thus larger and more beautiful blossoms were produced.

11

Figure 8. The beauty blossoms of three spikes for V3, P. Sogo Yukidian

Some plants were transported to the state of New York, USA. The microclimate

in the greenhouse for the growing stage was 22℃ (day) and 20℃ (night). The light

intensity was maintained at 16000 lux. In this condition, these plants did not have

enough sources for photosynthesis. The accumulated dry matter was insufficient for

further utilization. With decreasing greenhouse temperature with the season change

and the spikes were induced. The quality of spikes and blossoms did not appropriate

for market requirements.

12

Figure 9. The quality of spikes and blossoms of V3, P. Sogo Yukidian in

New York

From the illustration of the above case, the important of each characteristics of

variety need to be emphasized, which explains why many varieties of Phalaenopsis

have been sent to The Netherlands, some varieties have excellent flowering quality.

However, many varieties do not have accepted quality.

6. Selection of adequate varieties for The Netherlands

6.1. The greenhouse microclimate

The microclimate of the greenhouse for Phalaenopsis for The Netherlands is

described in Table 1. The day and night temperature are 28℃ and 26℃ for the

vegetative stage and e20℃ and 18℃ for the cooling phase. So the selection of

varieties of Phalaenopsis to provide to this country need to meet the requirements

of temperature and light intensity listed in Table 1.

13

6.2. Requirements of varieties for The Netherlands

The basic requirements for varieties are the genotype and plantlet conditions

The genotype and other conditions of adequate varieties are as follows.

A. Double or more spikes

B. Medium or large-sized of blossoms, at least 8 cm

C. Number of flowers at least 6 for each spike

D. Bright color of blossoms

E. Compact size, for more plants can be placed per square meter

F. No disease, insect damage, viruses, chemicals damage, salt accumulation in

the substrate. Leaves and roots are healthy.

About the author:

Professor Chiachung Chen, Ph. D.

Biosystems Engineering Laboratory

National ChungHsing University

250 KuoKuang Rd.,

Taichung, Taiwan 40227

Tel: 886-4-22857562, Fax: 886-4-22857135

Web site: bse.nchu.edu.tw

Email: ccchen@dragon.nchu.edu.tw