Several key technical points for off-season cultivation of coriander

1.Variety selection For off-season cultivation of coriander in summer and autumn, it is advisable to choose coriander varieties that are tolerant to damp heat, disease-resistant, highly stress-resistant, and of the large-plant, large-leaf type.

2.Seed treatment Coriander seeds are difficult to germinate under high-temperature conditions. Before sowing, use1%carbendazim wettable powder300times solution to soak the seeds for half an hour, then remove and wash them clean, then soak them in clean cold water for20hours or so, and then at20-25°C conditions to promote germination before sowing.

　　3.Land preparation and fertilization Choose a plot with convenient drainage and irrigation and loose, fertile soil. After the previous crop is harvested, plow deeply in time20-25cm and sun-dry for15days. To facilitate the use of shade netting, make deep-furrow high beds with a bed width of120cm, a height of20cm, and a furrow width of30cm. The coriander growing period is relatively short. In combination with land preparation, apply per mu decomposed human manure and urine3500kg and cake fertilizer150kg, and calcium-magnesium phosphate fertilizer50kg as base fertilizer. The surface soil of the bed should be finely broken up and leveled to facilitate uniform emergence of seedlings.

　　4. Sowing at the right time For off-season cultivation of coriander in summer and autumn, sowing is generally done from5mid-month to7early month, with a seeding rate per mu of1kg, which can both achieve relatively high yield and obtain a relatively high selling price. When soil moisture is suitable, broadcast evenly, then cover1-2cm. Cover with straw mats to preserve moisture and maintain soil moisture and promote seedlings,5-7days later remove them, and during this period pay attention to maintaining soil moisture.

　　5.Field management As summer and autumn temperatures gradually rise, this will affect the growth of coriander. Therefore, after removing the straw mats, promptly set up frames and cover with shade netting. The shade netting should be covered during the day and removed at night, strengthening ventilation to prevent seedlings from growing spindly and weak and to prevent disease. Because coriander has a short growing period, it is advisable to weed early, thin seedlings early, and apply quick-acting nitrogen fertilizer early. Generally, thinning should be carried out about7days after full emergence,2true leaves when final thinning is done, with a plant spacing of2-3cm. Usually water once every8days or so, and begin topdressing when seedlings are1cm high, applying per mu urea3kg and boron fertilizer10-15g. Afterward, in combination with irrigation, apply topdressing of ammonium bicarbonate or urea in stages250times. In the later stage, when applying foliar fertilizer, add an appropriate amount of potassium dihydrogen phosphate to promote leaf growth.2-4Next, when applying foliar fertilizer later, add an appropriate amount of monopotassium phosphate to promote leaf growth.

　　6.Pest and disease control For pollution-free coriander, pest and disease control should follow the principle of giving priority to prevention and supplementing with treatment, combining multiple control methods to keep pests and diseases within the smallest possible range.

　　1Agricultural control Base it on varieties with strong disease resistance, implement crop rotation, and avoid continuous cropping. Promptly remove diseased plants and diseased leaves in the field to reduce opportunities for pathogen infection. Strengthen fertilizer and water management to improve plant disease resistance.

　　2Physical and biological control Apply physical control techniques such as frequency-vibration insect-killing lamps, sex attractants, andBtpowder.

　　3Chemical control Diseases mainly include damping-off at the seedling stage, and viral disease, anthracnose, and leaf spot at the adult plant stage. After emergence5days, use the pollution-free fungicide3%polyoxin800times solution spray1times, afterward every7days polyoxin600times solution spray1times, for a total of2-3sprays, which can prevent damping-off, anthracnose, and leaf spot. To control viral disease, insect-proof netting can be used to prevent the aphids that transmit it from flying in; shading can be used to avoid a high-temperature and dry environment and reduce the occurrence of aphids; and20%imidacloprid wettable powder20g added to water50kg for foliar spraying, to thoroughly control aphids and prevent the occurrence of viral disease. For leafminer, use1%abamectin1500times solution spray.

　　7.Harvest About40days after sowing, it can be harvested. About15days before harvest, spray20-25ppmgibberellin, which can make the leaves elongate, increase branching, and result in high yield.