It takes 50 ~ 1 10 days for Chinese cabbage to form leaf bulbs. According to the growth cycle, it can be divided into two periods: vegetative growth period (germination period, seedling period, fruiting period, dormancy period) and reproductive growth period (bolting period, flowering period and pod setting period). It usually takes 3-4 days (commonly known as "heartbreak") from seed germination to cotyledon unfolding to real leaves exposing. You need soil moisture when you germinate, and you can sow when the soil is wet after rain. After sowing, it can be covered with leaves and sunshade nets, which can protect water from drought and prevent soil from hardening after rain. Water and fertilizer management: the watering method of "three waters and seven seedlings, five water jacket trees", that is, watering 1 time after sowing, watering the seedlings for the second time when they encounter arching soil, and watering the cotyledons for the third time. After the thinning seedlings are fixed, each plant is watered once. From the broken heart to the first leaf, the annual rings are scattered (commonly known as "Tuanshu").

Water and fertilizer management: when the seedlings grow 1-2 true leaves, the seedlings are thinned for the first time, leaving 4-5 plants in each hole, and extracting the seedlings with a small amount of nitrogen fertilizer combined with water; When the seedlings grow to 3-4 true leaves, carry out the second thinning, leaving 2-3 seedlings in each hole. After watering the thinning, apply nitrogen fertilizer to the weak seedlings. The third time, the seedlings are interplanted with 5-8 leaves, and each hole is reserved with 1 seedling, which is also called fixed seedling. Top dressing: Top dressing once after sowing. Apply 1000- 1500 kg of fully decomposed fertilizer or 10-20 kg of ammonium sulfate and 20 kg of potassium sulfate per mu.

Trenching is carried out on one side of the small ridge, and after fertilization, the soil is covered to close the gully. Water it once after topdressing, and water it again after 3-4 days. Keep the ground moist with logistics water; About 10 days before seedling formation, control water to promote the growth of leaf bulbs. The bulb is wrinkled when it is dark green, wilting slightly at noon, and when the center of young leaves changes from yellow-green to green, the seedlings squat down. Water and fertilizer management: when the rosette leaves are closed, the heart leaves begin to embrace the end of the squatting seedlings.

When watering for the first time, it is not advisable to water too much, with topdressing per mu 1000- 1500 kg and plant ash 100 kg; After covering 15-20 days, according to the "fertilizer supplement", rinse with water and apply decomposed bean cake fertilizer for 2-3 times, or apply compound fertilizer 15kg or potassium sulfate 10kg. Chinese cabbage needs more calcium and boron during its growth. Usually calcium deficiency is prone to dry-hot heart disease; The petiole of heart-shaped tissue will appear boron deficiency, from brown to dark brown, and the periphery of the leaf will die and the shape will be poor. After the formation of leaf bulbs, low temperature inhibited the growth and development of Chinese cabbage, and Chinese cabbage was forced to hibernate, relying on the nutrients and water stored in leaf bulbs to prepare for the breeding period.