Cabbage is the abbreviation of cabbage, and is also known as cabbage, cabbage, fennel white, lotus white, cabbage, etc. It is widely planted in various parts of my country. Due to different climatic conditions, the cultivation methods are quite different in different places.

In North China, Northeast China and Northwest China, early-maturing or medium-maturing varieties are selected, and seedlings are raised in winter, planted in mid-late spring, and harvested in late spring and early summer, which is called spring cabbage; Planting in early summer and harvesting in late summer and early autumn is called summer cabbage; disease-resistant and heat-resistant early and mid-maturing varieties are used to raise seedlings in summer, cultivate in summer and autumn, and harvest in autumn and winter, which is called autumn cabbage.

In the Yangtze River and Pearl River basins in my country, early and medium-ripening varieties with strong winter characteristics are often used, sown in early winter, the seedlings overwinter in the open field, and harvested in late spring and early summer of the following year, which is called overwintering spring cabbage; early and medium-maturing varieties are used in late summer. Sowing in early autumn and harvesting in winter are called autumn and winter cabbage. In some areas, disease-resistant and heat-resistant varieties are also used, sowing in late spring and early summer, and harvesting in summer and early autumn, which is called summer cabbage.

In recent years, many vegetable farmers in the north have selected early-maturing cabbage varieties with strong winter characteristics, and cultivated them in solar greenhouses or medium and small plastic sheds in winter and spring. In some cool areas or mountainous areas with higher altitudes, it is also possible to obtain better economic benefits by using early and mid-maturing varieties to raise seedlings in late spring and early summer, and cultivate them in off-season in summer. In alpine regions such as the north of the Great Wall and the Qinghai-Tibet Plateau, many areas often use one-season cultivation, that is, late-maturing varieties are used to raise seedlings in late spring and early summer, plant in summer, and harvest in autumn and winter.

There are many differences in cultivation techniques depending on the cultivation season and cultivation area of cabbage. Generally speaking, spring cabbage should be cultivated with strong winter varieties, and the sowing period should not be too early to prevent "unripe bolting"; , pest control.

As mentioned above, my country has a vast territory, and the cultivation methods and cultivation techniques of cabbage are different in different places. It is difficult to list the specific cultivation techniques here. The following is only a brief introduction to the cultivation techniques of open field spring and autumn cabbage in North China and the method to prevent unripe bolting of spring cabbage:

1. Technical requirements for the cultivation of open field spring cabbage

 Select early and mid-maturing varieties with strong winter characteristics and are not easy to "underripe bolting", and sow seedlings in a solar greenhouse (mid-late January) or a small bow shed (early and mid-January). Before sowing, the seeds are generally not germinated. The border should be raked and watered, and the seeds should be spread evenly. After sowing, it should be covered with sieved fine soil to keep moisture and prevent the seedling from cracking. Before emergence, the greenhouse should be kept between 15 and 25 °C as much as possible. Generally, the seedlings emerge in about 5 days. Pay attention to gradually releasing the air in time to keep the temperature between 10 and 20 °C. If the seedlings are too dense, you need to "thin the seedlings" in time to prevent the seedlings from growing too long. When the seedlings grow to about 3 true leaves (about mid-to-late February), the seedlings should be divided once, and the seedlings are moved to the nutrition pot. The seedbed greenhouse is generally controlled at 8~20℃. The seedlings grow to 6-7 true leaves in late March and are ready for planting. 7 to 10 days before planting, the seedbed should be ventilated to train the seedlings, and the minimum temperature of the seedbed can be gradually lowered to 3-5 ℃.

Before planting, choose a plot with fertile soil and flat terrain, apply good base fertilizer and make a flat border. The planting density is generally 4,500 plants of early-maturing varieties, 3,500-4,000 plants per mu of medium-early-maturing varieties, and 2,500-3,000 plants per mu of medium-maturing varieties. Water twice in a row, and then cultivating and squatting the seedlings twice, each time for 5 to 7 days, to prevent the seedlings from growing too long. Sufficient water and fertilizer should be supplied when starting to wrap the heart, and when entering May, pay attention to preventing aphids and cabbage. Early-maturing varieties begin to be harvested in mid-May, mid-early and mid-maturing varieties are harvested from late May to early June, and leaf bulbs should be harvested in time to prevent cracking.

2. Key points of cultivation techniques for autumn cabbage in open field

Choose disease-resistant and heat-resistant varieties, and make high borders on high terrain and easy irrigation and drainage. The sowing time in North China is generally from late June to early July. The top is covered with plastic cloth, and the border is covered with gauze, so that the nursery border can not only prevent rainstorms, but also ventilate and prevent insects. The seedlings are divided when there are about 3 true leaves, and the open fields are planted when the seedlings grow to 6 to 7 true leaves from late July to early August. In addition to flat terrain and fertile soil, the fields for autumn cabbage are also required to be easy to drain and irrigate to prevent waterlogging. The cultivation method is generally to plant the seedlings on the shady half slope of the ridge, and the planting density is generally 3500~4000 plants of early-maturing varieties; 2500~3000 plants of middle and late-maturing varieties. After slowing the seedlings, topdressing and splitting the positive ridges, so that the seedlings are in the middle of the ridges, immediately clear the ridges to facilitate drainage and irrigation. In the whole cultivation process, always pay attention to the control of pests and diseases.

3. Unripe bolting of spring cabbage and its prevention method

In recent years, there has been a growing preference for growing early spring kale. Many vegetable farmers have obtained better economic benefits by planting early-maturing spring cabbage, and some vegetable farmers subjectively violate the objective laws in order to strive for early-maturing spring cabbage. "Unripe Bolting".

Cabbage is a vernalized crop. When the seedling grows to about 7 true leaves, the leaf width is more than 5 cm, and the stem diameter is about 0.6 cm, it encounters a low temperature of 0~15 °C, and after 50~90 days, it can pass the spring. The phenomenon of "underripe bolting" occurred in the chemical conditions. Especially under the low temperature condition of 0~4℃, it is easier to cause "underripe bolting" through vernalization. The phenomenon of "unripe bolting" in early spring cabbage is closely related to the variety, sowing period, temperature management of seedbed, seedling size, early and late planting, management after planting and climatic conditions in early spring.

(1) It is related to the winter nature of the variety: Beijing early-maturing, Dieter 409, Yingchun and other varieties planted in the past have weak winter nature and are prone to "unripe bolting". 8398, Zhonggan No. 10, Zhonggan No. 11 and other early-maturing spring cabbage first-generation hybrids are prepared from self-incompatible lines with strong winter characteristics, and are not prone to "underripe bolting". However, if the cultivation management is improper or encounters severe cold weather in the late spring, "underripe bolting" will inevitably occur.

(2) The relationship with the size of the seedling: For large seedlings with more than 7 leaves, a maximum leaf width of 5 cm or more, and a stem diameter of more than 0.6 cm, after a period of low temperature to complete the development of the vernalization stage, "unripe bolting" will occur. ". The larger the seedling and the more vigorous the growth, the greater the possibility of bolting.

(3) Relationship with climatic conditions in early spring: If the temperature of early spring cabbage during seedling raising and after planting is abnormal, it is easy to cause "unripe bolting". For example, the average temperature in the western suburbs of Beijing in January 1991 was 1.5°C higher than that of previous years, and the average temperature in early and mid-February was 2.1°C higher than previous years. High, the seedlings grow fast, making them ready to pass the vernalization stage. The average temperature in late February was 1.5°C lower than previous years, the temperature after colonization was lower than previous years, and the average temperature in mid-to-late March was 0.8°C lower than previous years. Due to the long duration of the late spring cold and the large coverage area, early-ripening spring cabbage occurs in some areas north of the Yangtze River in my country, causing "unripe bolting".

(4) Relationship with the time of planting: The earlier the planting is, the seedlings are often too large by the time of planting. The longer the seedlings are under low temperature conditions, the more chances of vernalization and the greater the chance of "unripe bolting". Conversely, if the seedlings are properly sown late, the seedlings will not reach the size that can accept the low temperature, and even if the low temperature is encountered, "underripe bolting" will not occur.

(5) Relationship with seedbed temperature management: Even if the seedbed is not planted early, if the seedbed temperature management is high, the seedlings will grow faster, and it is easy to grow to a size that can accept low temperature. On the contrary, if the temperature management of the seedbed is low, even if the seedling is planted earlier, due to the slow growth of the seedling, the seedling has not grown to the size that can accept the low temperature by the time of planting.

(6) Relationship with early and late planting and management after planting: If early spring cabbage is planted early, especially if it is affected by the cold of late spring after planting, it is more likely to cause "unripe bolting". Because the temperature of the open field in early spring is lower than that of the seedbed, the planting is earlier, the temperature is low, the seedling is slow, and the seedling feels the low temperature for a long time, so the rate of "unripe bolting" is also high. However, when the seedlings do not dare to be planted at low temperature, the seedlings continue to grow rapidly in the seedbed, and "underripe bolting" will also occur after meeting the low temperature requirements of the seedlings. After planting, if you don't pay attention to squatting the seedlings, too much fertilizer and water will make the plant grow too vigorously, which will not only delay the wrapping, but also easily cause bolting. Especially those planted in small plastic arch sheds, the temperature is high during the day, the seedlings grow fast, and the temperature is low at night, which is more likely to promote "underripe bolting".

In order to strive for the early maturity and high yield of spring cabbage, and to prevent "unripe bolting" of early-maturing spring cabbage, in addition to selecting excellent varieties with strong winter characteristics, the following measures should be taken:

(1) Plant seeds at the right time, and control the temperature management of the seedbed. The suitable sowing time of early-maturing spring cabbage in North China should be sown in the greenhouse or improved Yang Qi in mid to late January. After the seedlings emerge, pay attention to the ventilation, and keep the temperature of the seedbed between 8 and 20 °C to prevent the seedlings from growing too long. Divide the seedlings once in the middle and late February, and plant them from the end of March to the beginning of April.

(2) Strengthen field management and pay attention to proper squatting in the early stage to ensure early maturity and high yield of spring cabbage. After the early-ripening spring cabbage is planted with slow seedlings, do not make the seedlings grow too vigorously in the early stage, and take measures to squat seedlings twice, that is, after slowing the seedlings and cultivating them, water them once every 7 days, and then cultivating them again, and then start fertilizing and watering after about 7 days. , 4~5 water can be harvested and listed. Early-maturing spring cabbage planted in a small plastic arched shed and covered with plastic film, the shed temperature is generally controlled not to exceed 25 ℃ to control the leggy outer leaves. Pay attention to top dressing and watering when starting to wrap the heart.

(Note: This article is reproduced for reference only)