Cultivation techniques of dwarf sunflower

Dwarf sunflower is an annual herbaceous flower of the genus Compositae. Its short plant, dense branches and leaves, large flowers, a wide variety, rich flowers, dark red, brown, copper, golden, lemon yellow, milky white and other colors, has a high ornamental value, can be potted or planted on the ground. it is an excellent material for arranging flower beds, flower borders and festivals. 1. The variety selects the big smile variety of dwarf sunflower, which has a plant height of 30 to 40 cm, a flower diameter of 10 to 17 cm, a bright golden petal and a black heart. It can blossom 50 to 55 days after planting, which is suitable for potted plants and flower beds. two。 The seedlings are sowed and propagated, which are generally sown in April. The optimum temperature for germination is 15 to 18 ℃. The seedlings can be sowed in shallow pots or shallow boxes, with loose media, good water retention, asepsis and so on. Sowing on demand is appropriate, sowing 2 grains per hole, covering 1 to 2 cm thick medium after sowing, in order to maintain the humidity needed for germination, increase the stability of seedling stage and reduce the occurrence of shelled seedlings. Generally germinate 7 to 14 days after sowing, pay attention to ventilation and cooling after emergence, control humidity, and gradually see the light. 3. Planting and maintenance when the seedlings come out one after another, one plant is left in each hole, and the seedling height is 7 to 8 centimeters. The basin soil should be sandy soil which is rich in humus and well drained. When planting, apply sufficient basal fertilizer to the bottom of the basin, and dig up the seedlings with more soil and less root damage, so as to make the plant recover quickly. Dwarf sunflowers like sunny and warm environment, not resistant to shade and cold. Fertilization should be applied once every 20 days during the growing period, but thin phosphorus and potassium fertilizer should be applied 2 or 3 times before flowering. Always keep the soil moist, especially when it is hot and dry in summer. In order to make the terminal bud of the main branch grow and develop healthily, the lateral (axillary) bud can be removed. A pillar should be set up for those with a slightly higher stem to prevent the wind from falling down. Artificial pollination during flowering can improve the seed setting rate. 4. The common diseases and pests in pest control are powdery mildew and black spot. During the onset of powdery mildew, the leaves began to produce white round powdery spots, which were enlarged and connected into one piece, and then there were brown spots on the powdery mildew layer, and the plant growth stopped. When black spot disease occurs, the leaves give birth to dark brown or light yellow disease spots of different sizes, and then develop into brown spots, which are connected into large patches, making the leaves black and withered. When the disease occurs, the residual plants can be removed and sprayed with 75% chlorothalonil wettable powder 500 times or 70% methyl topiramate 800 times for prevention and treatment. Insect pests are mainly caused by blind bugs and red spiders, which can be sprayed with 1500 times of omethoate EC or 73% propargite EC.