1. Key points of propagation and cultivation
Breeding offspring with seeds, peat soil is suitable for sowing. Seed dressing with new high-fat film before sowing can drive away underground pests, isolate virus infection and improve seed germination rate. Sunflower has a high demand for light and a wide temperature tolerance range, which is suitable for 15~30℃, but it still grows rapidly in summer. Because of the high light requirement, fast metabolism and large water demand, it is advisable to irrigate and water frequently to keep the soil moist and water it every day in summer. The best way is to mix organic fertilizer into the culture soil; In addition, chemical fertilizer can also be added according to plant conditions.
1 panicum miliaceum,1~ 3m high. The stems are erect, stout, round, angular and covered with white coarse bristles. Leaves are usually alternate, heart-shaped, ovate or ovoid, with acute or acuminate apex, 3 veins at the base, coarsely serrated edges, rough sides and long hairy stalks. Head inflorescence, extremely large, 10~30 cm in diameter, solitary at the top of stem or branch, often inclined downward. The involucral bracts are multi-layered, leafy, imbricate, hairy, flowering in summer, with yellow tongue-shaped flowers at the edge of inflorescence, which is fruitless. The middle of the inflorescence is a bisexual tubular flower, brown or purple, solid. Achene, obovate or ovoid oblong, slightly flat, with lignified skin, gray or black, commonly known as sunflower seeds. Sex is warm and drought-tolerant.
Sunflower sowing time: March-April
Suitable sowing temperature: 18~25℃
Budget time: 5~7 days.
Sowing method: Sow as needed, cover with soil about 65438±0cm, and bloom about 50~80 days after sowing.
Due to different varieties, the items are slightly different.
2. Pest control
The incidence of sunflower diseases and insect pests is low, and the main diseases are powdery mildew, black spot, bacterial leaf spot, rust (prevalent in high humidity period) and stem rot. When powdery mildew occurs, the leaves begin to produce white round powdery spots, which expand and connect together. Later, brown spots appeared on the powdery mildew layer and the plant growth stopped. At the onset of black spot disease, there are dark brown or yellowish spots of different sizes on the leaves, which later develop into brown spots, and the spots are connected into large pieces, which make the leaves black and die. It can be prevented by substrate disinfection, reasonable watering, increasing air circulation and intermittent spraying of protective fungicides. After getting sick, remove diseased leaves and residual plants and burn them centrally; At the initial stage of the disease, 500 times of 50% thiophanate-methyl wettable powder can be sprayed or treated with the same amount of Bordeaux solution. The pests that harm sunflowers are aphids, blind stinkbug, red spiders and scarabs. , 40% omethoate EC 1000 times and 73% propargite EC 1500 times can be sprayed.
Step 3: Pick cut flowers.
The outer ligulate flowers can be harvested when they are open. The vase life in water or preservative solution is 6-8 days in summer and 10- 15 days in winter. Generally, leaves should be removed during harvesting and packaging, and it is appropriate to leave 1 leaf at the top. Cut flowers are stored at 2℃~5℃ for about 1 week.