Biological features. Favorable temperature for seed germination is 20-22°C, while seedlings appear in 3-4 days. The optimum temperature for growth is 20°C, for head formation 12°C. The plant is a long day, but the transition to the stalking stage is facilitated by a long day only after incomplete vernalization. At 22°C the long day does not lead to the stem phase. The plant is relatively hardy to low light. In relation to moisture, the plant is extremely demanding. Prefers neutral or slightly acidic soils. Most of all it consumes nitrogen and potassium, less calcium and some phosphorus and magnesium.
Variety selection. Currently, four domestic varieties are recommended for cultivation in protected ground - Lenok, Polukochannaya, Rodnik and TSHA-2. These varieties are semi-headed type with fairly high resistance to edge burn. There are not many head varieties for cultivation in protected ground, due to the fact that so far it has not been possible to obtain varieties with high resistance to edge burn. True, recently new hybrids have appeared that, according to the originator companies, are suitable for growing in greenhouses: Asten (Ryk Zwaan), Elliot (Ryk Zwaan), Nerva (Enza Zaden), Akala (Enza Zaden) and Nepos (Enza Zaden).
Growing seedlings. Sowing dates - from the end of December to the end of July.
The technology of growing seedlings of Beijing cabbage differs little from growing seedlings of lettuce. For seedlings, cassettes with a cell size of 4-5x4-5 cm are used. The temperature regime depends on the final product, on a socket or a head of cabbage. When growing on a rosette, the following temperature regime is recommended: before the emergence of shoots, the air temperature is 20-22 ° C day and night, with the appearance of mass seedlings, the temperature is reduced for 7-10 days to 12-14 ° C during the day and 10-12 ° C at night (to to avoid stretching the hypocotyl genus), then the temperature is raised again to 16-18°C during the day and 14-15°C at night. When grown on a head of cabbage, the air temperature should be 22-24°C, at night 20-22°C from sowing to the formation of 1 true leaf, then 18-22°C.
Landing. Before planting, be sure to check the soil for the presence of keel, the reaction of the environment (pH = 6.0-7.0) and the concentration of water-soluble salts (0.3-0.5 mS/cm). Plant seedlings in moist soil. The planting pattern depends on the type of product, on a socket 15-20x15-20 cm, on a half-head 25-30x25-30 cm and on a head 35-40x35-40 cm.
Care. Not much different from what they do on a salad. The temperature regime depends on the type of product. When growing on a rosette: air temperature 18-20°C during the day and 14-15°C at night, on sunny days 2-3°C higher, soil temperature 17-19°C. For semi-heads: air temperature 18-20°C during the day and 14-15°C at night, from the beginning of head formation 15-17°C during the day and 13-14°C at night, at the end of cultivation 12-14°C during the day and 10-11 °С at night, on sunny days 2-3°С higher, soil temperature 17-19°С, at the end of cultivation 15°С. Head: air temperature 22-25°C during the day and 18-20°C at night, during the head formation period it is 3-5°C lower. Soil temperature is not lower than 18°С. Air humidity is the same as when growing lettuce, and soil moisture is 15% higher. Mistakes and shortcomings made when growing Beijing cabbage are the same as when growing lettuce.
Cleaning. Beijing cabbage is harvested in one step, the head is cut off and the lower rotten leaves are removed. Packed in boxes, tightly stacked, in several rows, the lower rows go up with heads of cabbage, the top ones go down with heads of cabbage. Harvested plants can be stored at a temperature of 5-8°C for up to 2-3 days, at a temperature of 0-1°C and RH 98-100% for up to a month. Heads of cabbage can be stored at a temperature of 0-1°C and high humidity for more than a month.
The yield of Beijing cabbage ranges from 3.5 to 14 kg/m2 and depends on the sowing date, variety, growing conditions and final product (per rosette, semi-head or head). According to our data, when sowing on January 9 and harvesting on March 28, the yield ranged from 6.0 to 7.7 kg/m2, depending on the variety.
Diseases. Under unfavorable growing conditions (1.8), plants can be affected by diseases, of which bacterioses are the most harmful (see ch. 1.10 for control measures). Of the physiological diseases, the marginal leaf burn is the most dangerous. Leaf edge burn (marginal burn) is one of the most typical and dangerous diseases, which, in case of mass damage, can lead to a complete loss of crop. It is the main deterrent for the widespread cultivation of Chinese cabbage per head in protected ground. The root causes of the disease are the same as on the salad. Control methods: adherence to technology, constant monitoring of the salt concentration in the soil (not more than 0.5 mS/cm), preventive treatments with 0.5% CaCl2 solution or 2.0% Ca(NO3)2 solution, starting from the stage of head formation and earlier.
Of the pests, aphids are the most harmful.