Commercial Floriculture

Green house cultivation - Environmental Factors

1. Light: Chrysanthemum flowering is very much influenced by the quantum and quality of light. Most of the cultivars require shorter days for flower bud initiation and development. Under long days they tend to remain vegetative.
2. Temperature: Based on temperature requirements chrysanthemum cultivars are classified into three.
i) Thermo-zero cultivars which flower at any temperature between 10-27oC but most constantly at 16oC night temperature.
ii) Thermo-positive cultivars in which continuous low temperature between 10-13oC inhibit or delay flower bud initiation and at 27oC there will be rapid initiation but delayed flowering.
iii) Thermo-negative cultivars in which bud initiation occurs at low temperature delay bud development.
• The effect of night temperature is more pronounced than day temperature and night temperature of 16-20o C was found optimum for most of the cultivars.
• High temperature may cause floral distortion and low temperature may some time cause discoloration of the flower.
3. Relative humidity: The chrysanthemum requires a moderate humid condition of 70 to 90 per cent and hence it should be preferably grown in places there will not be any rains during flowering time.

^Top