Introduction
Carnation (Dianthus caryophyllus) is one of the most popular cut flowers grown commercially in greenhouses due to its long vase life, attractive color range, and good transportability. It thrives well under controlled environmental conditions that can be provided in protected structures like greenhouses.
Climatic Requirements
- Optimal temperature: 20–25°C during day and 10–15°C at night.
- Relative humidity: 50–60% is ideal.
- Requires ample light for better growth and flower production (minimum 10,000 lux).
- Excessive heat or humidity leads to disease problems and poor flower quality.
Soil and Media
- Well-drained, porous, and sterile media is ideal.
- Commonly used media: cocopeat, perlite, vermiculite, peat moss.
- Soil pH: 6.0 to 7.0; EC should be below 1.0 dS/m.
Propagation
- Propagated through terminal cuttings from disease-free, healthy mother plants.
- Cuttings should be 4–6 cm long with 3–4 pairs of leaves.
- Rooting is done in trays using cocopeat, with bottom heat and misting.
Planting
- Plant spacing: 15–20 cm between plants and 20–25 cm between rows.
- Density: 25–30 plants/m² for optimum yield.
- Support netting is required in 3–4 layers to keep stems upright.
Irrigation and Fertigation
- Drip irrigation is most suitable to maintain proper soil moisture and avoid fungal infections.
- Fertigation using water-soluble fertilizers like NPK (19:19:19), calcium nitrate, magnesium sulfate is practiced.
- Micronutrients like Fe, Zn, Mn are also supplemented.
Training and Pinching
- Pinching: Done to encourage side shoots and more flower buds.
- Single pinching is done 3 weeks after planting; sometimes double pinching is done for better quality.
- Support netting layers (3–4) are used to hold stems upright.
Flower Harvesting
- Harvest when outer petals of flowers just begin to unfurl.
- Use sharp, sterile tools to cut stems at an angle.
- Harvesting time: early morning or late evening.
- Flowers are immediately placed in clean water to prevent wilting.
Pest and Disease Management
- Common pests: Aphids, thrips, spider mites, whiteflies.
- Diseases: Fusarium wilt, Alternaria, rust, botrytis blight.
- Use of sticky traps, proper ventilation, and biological controls is advised.
- Regular sanitation and use of disease-free planting material is essential.
Post-Harvest Handling
- Grading of flowers based on stem length and bloom quality.
- Storage at 2–4°C in cold rooms to prolong vase life.
- Packing in bundles of 20 stems using plastic sleeves and boxes for transportation.
Extra Activities to Improve Quality
- Use of LED grow lights in low-light seasons to maintain photoperiod.
- CO₂ enrichment to 800–1000 ppm in greenhouse improves photosynthesis and yield.
- Use of mulching to control weed and maintain moisture.
- Regular pruning of non-productive shoots and removal of diseased material.
- Application of growth regulators like gibberellic acid (GA₃) for stem elongation and better flower opening.
Conclusion
Carnation cultivation under greenhouse provides a profitable venture due to high demand and quality control. With proper care, training, fertigation, and additional quality-enhancing practices, farmers can achieve high yields with export-quality flowers throughout the year.
