Greenhouse cultivation of orchids is a specialized horticultural practice that involves growing orchids in a protected and controlled environment. In greenhouses, essential parameters such as temperature, humidity, light intensity, and ventilation are precisely regulated to create a microclimate conducive to optimal orchid growth. This approach enables the year-round production of premium-quality flowers with consistent growth habits, enhanced color intensity, uniformity, and longer post-harvest shelf life.
1. Importance of Greenhouse for Orchid Cultivation
- Orchids are extremely sensitive to fluctuations in their environment and require stable conditions for successful cultivation.
- Greenhouses offer protection from environmental stress like heavy rainfall, strong winds, frost, and excessive heat or sunlight.
- They minimize the incidence of pest and disease outbreaks by maintaining cleanliness and controlled humidity levels.
- Provide an ideal habitat that supports propagation, flowering, and overall plant health regardless of outdoor climate variations.
2. Environmental Conditions for Orchid Cultivation
- Temperature: Ideal range is 18°C to 30°C depending on the orchid species.
- Humidity: Maintain 60% to 80% humidity consistently for healthy growth.
- Light: Bright, indirect or diffused sunlight is preferred. Direct sunlight can scorch leaves.
- Ventilation: Proper air circulation is necessary to reduce fungal diseases and promote transpiration.
3. Suitable Orchid Varieties for Greenhouse Cultivation
- Phalaenopsis (Moth orchid)
- Dendrobium
- Cymbidium
- Oncidium
- Cattleya
4. Growing Media
Orchids require loose, well-aerated, and well-draining media that allows root respiration. Commonly used media include:
- Charcoal pieces
- Brick pieces
- Coconut husk chips
- Sphagnum moss
- Perlite and bark mix
5. Potting and Planting
- Use plastic or clay pots with proper drainage holes to prevent waterlogging.
- Repot every 1-2 years or when the media begins to decompose.
- Orchid roots should be placed just above the medium; avoid deep planting to prevent rot.
6. Irrigation and Fertigation
- Watering should be light but frequent, ensuring slight drying between applications.
- Use soft or filtered water; avoid chlorinated water.
- Apply a balanced liquid fertilizer (20:20:20) weekly at half strength.
- Flush media monthly to prevent salt build-up from fertilizers.
7. Training and Support
- Flower spikes should be trained with bamboo sticks or floral wires for straight upright growth.
- Staking prevents breakage and ensures aesthetically pleasing flower arrangements.
8. Pest and Disease Management
- Common pests include aphids, mites, thrips, and mealybugs.
- Disease threats: Root rot, bacterial soft rot, and fungal leaf spots.
- Apply neem oil or appropriate insecticides/fungicides as needed.
- Maintain hygiene, remove dead tissues, and isolate infected plants promptly.
9. Special Activities to Improve Quality and Productivity
- Shading Nets: Help control light exposure and reduce temperature during peak sun hours.
- Fogging Systems: Maintain desired humidity levels during dry conditions.
- CO₂ Enrichment: Boosts plant metabolism, leading to faster growth and better flowering.
- Use of Growth Regulators: GA₃ (Gibberellic acid) can be used to enhance flower initiation and spike elongation.
- Grading & Sorting: Post-harvest classification ensures consistent quality for the market.
- Pollination Control: Avoid uncontrolled pollination to maintain hybrid purity.
- Environmental Monitoring Sensors: Sensors and automation systems help maintain uniform conditions throughout the year.
10. Harvesting and Post-Harvest Handling
- Harvest when 2-3 flower buds are open to ensure maximum vase life.
- Trim spikes and place in clean water immediately after harvest.
- Sort flowers based on color, size, and freshness.
- Pack in ventilated boxes with cushioning material to avoid damage during transport.
- Store in cool, humidified chambers (10-12°C, 90% RH) to extend shelf life.
Conclusion
Greenhouse cultivation of orchids offers a modern and efficient way to produce high-quality flowers with consistent characteristics and better commercial value. By utilizing advanced techniques like CO₂ enrichment, fogging, shading, precision irrigation, and post-harvest grading, growers can optimize both quantity and quality. The controlled environment reduces risks and extends the productive season, making orchid cultivation more sustainable and profitable.
