Types

Based on Plant Morphology

1. Sympodial 

This is the most common growth pattern among orchids, and the majority of species grow in this manner.

• Growth pattern: The plant grows horizontally along a main, stem-like structure (called a rhizome) that spreads across the ground. Growth ceases at the end of each season, and a new shoot emerges from the base or rhizome the following year.
• Key feature: They typically form pseudobulbs. These are swollen, bulb-like sections of the stem that store water and nutrients to help the plant survive during periods of drought.
• Examples: Cattleya, Dendrobium, Cymbidium, and Oncidium.

2. Monopodial

This pattern features an upward-growing axis without a branching horizontal system.

• Growth pattern: The orchid grows vertically from an apical bud (growing tip). The stem continues to elongate each season vertically, with new leaves constantly emerging at the top.
• Key characteristic: They lack pseudobulbs or rhizomes. Since they do not possess these fleshy storage organs, they generally require more consistent watering. Flowers emerge from the stem nodes between the leaves.
• Examples: Phalaenopsis (Moth Orchid), Vanda, and Aerides.

Growth Habit by Environment

1. Epiphytes: Plants that attach themselves to trees or branches and take root; their roots absorb moisture from the air and rain. Phalaenopsis, Cattleya
2. Terrestrials: Orchids that grow on the ground, directly in the soil or in piles of decaying forest leaf litter. Paphiopedilum, Cymbidium
3. Lithophytes: Orchids that grow on rocks, securing themselves in crevices and obtaining nutrients from moss or debris on the rock surface. Certain Laelia and Dendrobium species

 Cultivation Of Dendrobiums: Growing Dendrobium is easy and yields good profits for farmers, as these plants produce abundant flowers and bloom readily. They are cultivated in 50% shade houses—either on benches or in pots—using coco-fibre as the growing medium. Typically, they produce 10–12 flowering stems ranging from 35 to 60 centimetres in length, and these stems remain fresh for a long time.

Cultivation Of Mokaras, Arandas, Arantheras, Vandas: These are predominantly sun-loving orchids that generally require 30% shade. They are grown in a growing medium—either directly on the ground or on benches—or in wooden baskets. Compared to Dendrobiums, they require more water and fertiliser. They produce approximately 4–6 flower spikes annually; the blooms remain fresh for a long time, though the stems are short.

Cultivation Of Oncidiums: Plants of this species are grown much like Dendrobiums, with the slight difference that they require a somewhat cooler environment; this is because their pseudobulbs are able to store more nutrients in cooler regions. They produce abundant flowers and can form flower clusters up to a meter long, although the individual flowers are small.

Varieties

Dendrobium

Variety	Colour
New Sonia Bom	Dark Purple
Sonia 17M	Dark Purple
Sonia Red	Purple
Genting Casino	Purple
Burana Jade	Green
Sakura Pink	Light Pink
Boonchoo Gold	Yellow Red Lip
Genting Supreme	Blue
Ahulani Hinojosa	Brownish Orange
Kyomi Beauty	Dark Green
Burana Green	Green

Oncidium

Variety	Colour
Onc Grower Ramsey	Yellow
Onc Taka	Yellow
Onc. Sharon Baby	Pink With Spots

Mokara

Variety	Colour
MK Chark Kuan Pink	Orange, Red
MK New Nora Blue	Blue

Aranda

Variety	Colour
Iskander	Yellow
Christine Alba	White/ Red Spot

Vanda

Variety	Colour
Vanda Marlie Dolera	Purple

 

Climate
To grow this tropical orchid, ideal conditions include a 75% shade-net house, 70–80% humidity, daytime temperatures of 21–29ºC, nighttime temperatures of 18–21ºC, and a light intensity of 1500–2000 foot-candles. In areas with heavy rainfall, the shade-net house should be equipped with protection against the rain.

Light: Light is essential for the proper growth of orchids. Generally, they prefer filtered sunlight. While they can be kept in bright sunlight, doing so may scorch the leaves. The ideal condition is when the leaves are a light green colour rather than dark green. If the leaves turn yellow, the plant should be moved to a location with less sunlight. Similarly, the sudden appearance of brown or orange spots on the leaf tips or curved areas indicates excessive heat. Sometimes, plants produce pigments—often plum-colored—to darken their leaves; this phenomenon is known as a ‘suntan.’ It may manifest as spots or a darkening of the entire leaf, serving as a protective mechanism against burning. Light requirement – For growth: 5,000–8,000 lux, For flowering: 8,000–15,000 lux.

Growing media: Most common potting mixture consists of charcoal, broken pieces of bricks and tiles, coconut husk and fiber.

Containers and support : perforated earthen pots are ideal and the plants are staked with bamboo sticks.

Propagation:

By dividing clumps, using keikis, back bulbs, and tissue-cultured plants.

For commercial cultivation, tissue-cultured plants from recognized or reliable nurseries are used. Vegetative propagation is very convenient for small-scale home gardens.

1. Stem Cutting: Stem cuttings that are 40–50 cm long and possess at least two well-developed aerial roots (roots hanging in the air) are ideal. If shorter cuttings are planted, it will take longer for them to flower.
2. Layering: In monopodial orchids like Vanda, layering performed about 20–30 cm below the apex (growing tip) is successful. The cut section can be covered with a moist medium. Once roots emerge, the layered section can be detached.
3. Division: This involves splitting large clumps into smaller sections. Each section should have at least 4–5 shoots, including older ones. This method is suitable for Dendrobium, Cattleya, etc.
4. Off-shoots or keikis: Some orchids, such as Dendrobium, produce small, rooted plantlets at the nodes of their pseudobulbs. These are called ‘keikis’ (meaning ‘babies’). Once they have grown sufficiently, they can be carefully separated from the parent plant and potted individually, or attached to a coconut husk mount to allow for further growth.
5. Back bulbs: The older shoots or stems of sympodial orchids, which are physiologically less active, are referred to as back bulbs. These can be detached from the main plant and laid flat on a moist medium. After some time, roots will emerge and new shoots will sprout. They can then be separated and planted.

 Irrigation: Use mist or overhead sprinklers to provide water and maintain moisture. The water should be free from harmful chemicals or impurities. Water requirements depend on the weather, the soil (substrate), and the age of the crop. The irrigation system should be capable of delivering 5 to 12 litres of water per meter per hour. Along with irrigation, proper drainage is essential for the plants.

Nutrients: Starting 30 days after planting, apply a 0.2% NPK (20:10:10) foliar spray every week.

During the initial growth phase, a fertilizer mixture with a 1:1:1 ratio is required every two weeks. Larger plants require a 3:1:1 ratio mixture before flowering and a 1:2:2 ratio mixture during the flowering stage. Organic fertilisers—such as a mildly fermented solution of cow dung manure (1:25), oil cake (1:10), cow urine (1:25), and tender coconut water (1:20)—are also highly beneficial; these can be applied 2 to 3 times a week in tropical climates.

Growth regulators: Growth Regulator: Spray GA3 (50 ppm) every two months, starting 30 days after planting.

Repotting

Orchids require regular repotting, typically every two to three years.

• When the plant grows large and begins to outgrow its pot.
• When the potting medium or material deteriorates.
• When the plant needs to be separated or divided.
• It is best to repot epiphytes (plants that grow on trees) annually.
• The ideal time for repotting is when new roots emerge from the base of the previous year’s growth.
• For monopodial climbers (upward-growing vines), repotting or division should be done when new leaves and roots begin to appear at the top.

Separating or Dividing Plants

When a plant grows into a large clump consisting of two or three old stems (canes) and new shoots, it is separated before being repotted. Each separated section should include at least one stem that is at least two years old, one new shoot, and some new roots.

Harvest
Dendrobium flowers reach full maturity 3 or 4 days after blooming. They are harvested only when fully open, as flowers cut before maturity would wilt before reaching the wholesaler. Immediately after harvesting, the bottom 0.75 cm of the stem is trimmed, and the flower is placed in a tube containing fresh water mixed with a preservative. Harvest the flower spike when 75 per cent of the flowers have opened, and the remaining buds are still closed.

Post harvest handling:

Pulsing	:	8-HQC 500 ppm + Sucrose 5% for 12 hrs
Holding solution	:	AgNO3 25 ppm + 8-HQC 400 ppm + Sucrose 5%
Wrapping material	:	50 gauge polythene with base of spikes dipped in 8-HQC 25 ppm

 

After harvesting, the stems are placed in buckets of water and stored at a temperature of 7 to 10°C. Depending on the season and variety, their vase life can range from 5 days to 6 weeks.

The flowers are packed in single-use boxes measuring 100x15x11.5 cm. Depending on the number of flowers per stem, 25 to 30 stems are packed in each box.

Yield:
8 – 10 spikes/plant/year

INSECT PEST MANAGEMENT:

1. Slugs and snails: Slugs and snails gnaw on plant parts, creating round holes. They can damage a large number of plants in a very short time. Small snails and slugs can also attack the root tips of plants.

Control

• They can be effectively controlled by applying slug pellets to pots and the ground.
• Apply Metaldehyde 6% granules to the soil or garden beds at a rate of 0.7 grams per square

2. Mites: Red spider mites are found on the undersides of leaves. They suck sap from the leaves, causing them to become somewhat distorted and turn silvery in colour.

Control

• Mites can be controlled by spraying fresh water.
• Spray Karathane (0.5 ml/L), Kelthane (1 ml/L), Magister (1 ml/L), or Vertimec (0.4 ml/L).

3. Caterpillars: These sometimes attack new leaves and flowers.

Control

• Spray Lannate (1 g/L), Metasystox (1 ml/L), or Decis (0.5 ml/L).

4. Aphids or scale insect: Brown scale and balsam woolly aphids are found in clusters on flowers, leaves, and roots, making them difficult to control with chemical sprays. Aphids can be identified by white deposits on the plants, while brown scale is recognized by oval-shaped bumps on the upper and lower surfaces of the leaves. Their secretions form a sticky layer on the plants, which turns black due to the growth of black mold.

Control

• Hoeing the soil around the plants.
• Applying Thimet to the soil (2 g/pot).
• Spraying with Dimethoate (2 ml/liter).

DISEASE MANAGEMENT:

1. Bacterial disease:

I. Pseudomonas cattleyae:- This is the most significant bacterial disease affecting Phalaenopsis.

Symptoms:

The disease is characterized by distinct brown spots on the leaves; these spots appear oily and are surrounded by a yellow halo. In the early stages of infection, a deep depression or pit is visible on the leaf.

Control:

• Use high-quality, healthy planting material.
• Prune plants regularly (remove diseased plants).
• Maintain optimal nitrogen levels.
• Maintain appropriate relative humidity.
• Spray with Streptocyclin @ 0.3 g/L or Kasu B @ 1.25 ml/L. 

II. Bacterial soft rot (Erwinia carotovora): Plants infected with this bacterium develop wet spots on the leaves, which have a foul smell and spread rapidly. Eventually, within a day or two, the leaf becomes completely soft and sticky.

Control:

• Use good and healthy planting material.
• Prune plants regularly (remove diseased plants).
• Spray hydrogen peroxide 20% (5 ml/litre).
• Spray streptomycin sulphate (0.2 g/litre).

2. Fungal diseases:

III. Botrytis: Numerous small brown spots appear on the flowers. This disease occurs when flowers remain wet in the evening or when humidity levels in the air are very high.

Preventive measures:

• Avoid excessive moisture and prolonged wetness of leaves and flowers.
• Spray with Quintal (0.5 g/liter of water).

IV. Fusarium: A black triangular spot forms on the underside of older leaves, with yellow-red colouration visible along the edges. The leaf eventually drops off completely. Fusarium often occurs when the root collar region of the plant remains wet for an extended period.

Control:

• Avoid overwatering.
• Drench the soil with Topsin or Roko (2 g/liter of water).

V. Rhizoctonia spp.: Rhizoctonia primarily affects the crop on the substrate when planting is done too deeply, and growth is poor. Under such conditions, the fungus becomes parasitic. Young leaves become infected when they come into contact with the substrate. It can also damage the roots.

Control:

• Relative resistance to Rhizoctonia solani can be enhanced through good air circulation and proper drainage.
• Soak substrate with a fungicide (Bavistin or Benomyl 0.2%) at 3 g/L before planting.

Vi. Althelia rolfsii (Sclerotium rolfsii): This fungus attacks parts of young plants that are in extensive contact with the substrate. Warm and humid conditions favour its growth. White fungal mycelium develops on the substrate, within which orange-brown, mustard-seed-sized fungal structures (sclerotia) rapidly develop.

Control:

• Spray with Quintal or Rovral at a rate of 1 g/L.

 

3. Moulds: Excessive fluctuations in humidity or EC (electrical conductivity) can damage the roots, allowing moulds to attack the tissues. In case of root problems, the EC should be kept very low, the pot temperature should be kept very high, and the substrate should be kept somewhat dry for some time.

 

4. Viral disease: Infected plants have poor growth, flowers are small, and they do not develop fully. This also includes discolouration of flowers and the appearance of chlorotic (yellow) or necrotic (dead tissue) spots on leaves.

Control:

• Use healthy planting material.
• Prune plants regularly (remove diseased plants).

 

5. Root problems:This usually occurs when there are large fluctuations in nutrient and water content as well as substrate temperature. Excessive irrigation and poor drainage can also cause root decay. If the roots are unable to provide water and nutrients to the plant, the edges of the leaves become weak and their colour fades.

Control:

• Avoid fluctuations in nutrients and water quality.