What conditions must be met for cut chrysanthemum cultivation?
1. Light.
Autumn chrysanthemums are typical short-day plants. Their vegetative growth stage generally requires a day length of no less than 14 hours, and their reproductive growth stage generally requires a day length of no more than 12 hours. Supplemental lighting for rooted cuttings can prevent premature flower bud formation. The duration of supplemental lighting for chrysanthemums depends on the variety and cultivation fertilizer and water conditions. The correct supplemental lighting requirements are as follows: (1) One 100-watt incandescent bulb every 3 m, at a height of 1.5 m, ensuring that the weakest light area is above 50 LUX. (2) Generally, a 4-hour night-interruption supplemental lighting method is used, that is, dividing one long night into two halves; if midnight is the end of the night, then supplemental lighting is provided from 22:00 to 2:00.
2. Temperature.
Temperature has a great influence on chrysanthemum growth. Each growth and development stage has different temperature requirements. Temperature plays an important role in the rooting of rooted cuttings, and the seedbed uses bottom heating. Before rooting, the daytime temperature should be no lower than 21°C, and the nighttime temperature no lower than 18°C. For the first 40 days after planting, the minimum nighttime temperature should be no lower than 16°C, and the maximum should not exceed 32°C, keeping the daytime temperature 5-8°C higher than the nighttime temperature. During flower bud differentiation, the minimum nighttime temperature is 18-20°C. After flower bud differentiation, the nighttime temperature drops to 16-17°C, and the daytime temperature does not exceed 30°C.
3. Water.
After planting, ensure sufficient water. When the seedlings are about 30 cm tall, control watering to ensure a smooth entry into the flower bud differentiation stage. The degree of water control should be such that the lower leaves slightly wilt at noon. After flower bud differentiation, that is, when the flower buds are the size of mung beans, replenish water in time and water thoroughly.
4. Carbon dioxide.
Under sunny winter conditions, the greenhouse needs sufficient carbon dioxide. Start supplying it 1 hour before sunrise at 750-1000 PPM, and stop supplying it 1 hour before sunset. During ventilation and air exchange, do not supply carbon dioxide.
5. Soil.
The pH requirement is 6.5-7.0, and sandy loam soil with good aeration and drainage is preferable.