1. temperature management: in spring, the nursery emphasizes heat preservation and disease prevention, the seedbed is covered with multilayer films, and electric heating wires are laid on the ground. The temperature management is changed by the method of "two highs and two lows", that is, before emergence, the temperature of seedbed is kept at 30 ~ 32℃ during the day and at 18 ~ 20℃ at night to promote the seedlings to bloom; Before the first true leaf is unfolded, the bed temperature should be appropriately reduced to 25 ~ 28℃ during the day and to 15 ~ 16℃ at night to prevent high seedlings; When the third true leaf appears, the bed temperature should be properly increased, which should be kept between 30 ~ 32℃ during the day and between 18 ~ 20℃ at night to promote the early appearance of true leaf. One week before sowing, the seedlings gradually adapted to the field environmental conditions after low temperature exercise.
2. Water management: Water should be strictly controlled at seedling stage, and appropriate watering should be carried out according to the degree of dryness and wetness of the seedbed bowl before noon on sunny days. After watering, cover with plastic film after the water on the plant surface and soil surface evaporates and the water stains are dried.
3. Humidity and light management: Ventilation and humidity reduction is the key to prevent seedling diseases. Therefore, after sufficient sowing, the plastic film in the shed should be uncovered as far as possible within the scope of bed temperature to increase ventilation and reduce the air humidity of the seedbed. In rainy weather, short-term ventilation should be carried out around noon to reduce humidity and increase light.