Key points of planting techniques of Chinese cabbage in summer

1. selecting excellent varieties: selecting excellent Chinese cabbage varieties with strong heat resistance, strong resistance and good high yield such as heat resistance No. 45, Xiafeng and Xialu. 2. Sowing time: The suitable sowing time in summer is until the end of July. Third, land preparation and ridging: after harvesting the last crop, apply decomposed organic fertilizer 3000~5000 kg, ternary compound fertilizer 75 kg, calcium superphosphate 20 kg, zinc sulfate 10 kg per mu, deeply plow and rake after fertilization, so as to make the land flat. In order to facilitate drainage, it is best to use high ridges or high ridges when cultivating, with a ridge spacing of 40 cm and a ridge width of 100 cm. In order to prevent the occurrence of diseases and insect pests, 0.75 kg of thiophanate-methyl can be mixed with 10 kg of fine soil per mu and buried under the ridge. 4. Sowing method: in order to save seeds during direct seeding, it is better to sow in holes, plant spacing is 33~37 cm, row spacing is 40 cm, 4500~5000 plants are planted per mu, seed amount per mu is 50~100 g, fine soil 0.5 cm thick is covered after sowing, and it is flattened and compacted. 5. Field management 1. Thinning and fixing seedlings: thinning seedlings for the first time at 3~4 leaf stage and fixing seedlings at 5~6 leaf stage. Thinning seedlings, seedlings as far as possible do not hurt the roots, in case of soft rot root system, 4500~5000 seedlings per mu. 2. Fertilizer and water management: summer temperature is high, soil moisture evaporation is fast, should always keep the soil moist, prevent uneven soil moisture. In high temperature, dry weather should increase the amount of watering, rain or timely drainage after rain, in case of field water caused by rotten roots. Summer cabbage is watered once 10~15 days before the heart is wrapped, and then intertilled and squatting seedlings are irrigated. After squatting seedlings are watered, the fertilizer is applied once again. Pay attention to maintaining soil moisture during the ball setting period. When the ground is white, water it in time. In combination with watering, apply 10 kg urea or 15 kg ammonium sulfate per mu. The main application is hole application or furrow application. The fertilizer application point should be 8~10 cm away from the plant to avoid root damage. Stop watering 5 - 7 days before harvest. 3. Vegetable field covering: for heat preservation weeding, after seedling setting in the vegetable field with wheat straw or straw covering. 4. Pest control: summer cabbage main diseases are downy mildew and soft rot, appear after the disease plant should be removed in time. When downy mildew is controlled, it can be controlled by spraying 40% ethyl phosphorus aluminum wettable powder 200~300 times or 50% ridoxycycline manganese zinc 500~600 times at the initial stage of disease. The soft rot can be controlled by spraying 200~ 300g of Fengchanling on 100kg of water per mu at the initial stage of disease, or by spraying 3000~4000 times of agricultural streptomycin wettable powder. The main pest of summer cabbage is cabbage caterpillar, which can be controlled by card and green treasure or one time net.