1. Seedling cultivation. 1. Seedling raising time: Most areas in North China and south of the Huanghuai River Basin can raise seedlings in spring and autumn. Spring seedlings can be covered with film at the end of February and early March to protect the seedlings. In autumn, sow seeds in early or mid-October. 2. Seeding rate: Generally, 150-180 square meters of onion garden can be transplanted into one acre of land, and 0.5 kg needs to be sown. 3. Seed treatment: In order to reduce seedling diseases, soak the seeds with 0.1% carbendazim solution for about 1 minutes, wash them with clean water multiple times in a timely manner (to avoid phytotoxicity), and then soak the seeds with clean water for 1-3 Sowing can be done within hours. 2. Colonization 1. Planting time: Chinese giant onions raised in spring are generally planted from early June to early July. When the seedlings grow to a height of 30-40 cm and a transverse diameter of 1-1.5 cm, they are suitable for transplanting. 2. Land preparation and ditching: For plots where green onions are planted, litter and weeds should be removed immediately after the previous crop is harvested (no green onions and garlic stubble), and 5000-10000 kg of farmyard manure and 30 kg of diammonium phosphate should be applied. Dig deep. The trench should be oriented north-south to ensure even light reception and reduce the lodging of green onions caused by strong north winds in autumn and winter. The trench is about 0.33 meters deep and 0.75 meters wide. 3． Seedling raising and seedling selection grading: The seedbed should be watered 1 times 1-2 days before seedling raising, and the soil should be shaken off when raising seedlings. Seedling selection and grading. Eliminate sick, disabled seedlings and mossy seedlings, and divide the seedlings into three levels: large, medium and small. Those that cannot be planted on the same day should be placed in a cool place with the roots facing down to prevent the seedlings from becoming hot, yellowing or rotting. 4. Planting: The methods of planting green onions include the method of draining and filling the soil; the method of inserting and filling the holes with green onions. Sprinkle 1-2kg of carbofuran into the bottom of the ditch per acre, cover the soil to a depth that does not bury the leaves, and plant 15,000-20,000 plants per acre. 3. Field management 1. Watering: The over-summer stage of seedlings is during the rainy season of hot summer. Pay attention to drainage after rain to prevent large-scale irrigation in onion ditches, which will cause the root system to be deprived of oxygen and cause rot. Watering is generally not done during this period to allow the roots to renew quickly and the plants to turn green. In early August, the temperature is still high, the plant growth is still slow, and the water requirements are not high, so watering should still be limited. If drought occurs, water in the early morning to avoid watering at noon, which will suddenly lower the ground temperature and affect root growth. After the summer heat and before frost, green onions enter their peak growth period. On average, they can grow 1 leaves every 7-8 days. The higher the phyllotaxis, the larger the leaves and the longer the life of each leaf. During this period, due to the rapid growth in weight of leaves and green onions, water demand also increases greatly. It should be combined with top dressing and soil cultivation, and water should be poured 1 times every 4-5 days. The amount of water should be large, and a water dam should be built in the onion ditch to ensure that each ditch has enough water and is poured evenly. If there is drought and little rain, insufficient watering will seriously affect the growth rate and yield of onions. Generally, high-yield plots need to be watered 8-10 times at this stage. After the frost, the temperature drops, the green onions are basically mature, and the pseudostems (white green onions) enter the full stage. The plants grow slowly and require less water, so the soil still needs to be kept moist. The pseudostems are filled with pulp, making the mesophylls thick and full of glue, making them white, tender and plump. During this period, water should be irrigated more than twice to meet growth needs. Water should be stopped 7-10 days before harvesting to facilitate harvesting, storage and transportation. 2. Timely top dressing is an important measure to obtain high yield and high quality of green onions. (1) Early growth stage of green onion: In early to mid-August, leaf fertilizer should be applied 1 times. Apply 1000-1500 kilograms of farmyard manure and 7-10 kilograms of diamine phosphate per acre, till and mix well, and hoe in the ditch. Then pour water 1 times to promote the growth of green onions and provide for the growth and growth of leaves. Medium (2) The peak growth period of green onions: after late August, it is the fastest period for the production of green onions. Onion plants grow taller quickly and become whiter and thicker, requiring a lot of water and nutrients. At this time, the fertilizer should be pursued, and N, P, and K should be pursued in 2-3 times with equal emphasis. For the first time, 4000-5000 kilograms of decomposed farmyard manure or 15-20 kilograms of potassium sulfate can be applied to both sides of the onion rows. After cultivating, the soil will be built into ridges and watered. For the last two top dressings, 15-20 kg of ternary compound fertilizer can be spread between the rows and watered after cultivating. 3． Soil cultivation: Chinese giant onions should be cultivated while strengthening the supply of fertilizer and water, which can extend the length of the green onions and improve the quality of the green onions. Through cultivating between rows, cultivating the soil in stages, the ridge soil is packed into the onion ditch. By the end of August and beginning of September, the ditch will be leveled. In the future, the soil must be cultivated in stages to make the original ridges become furrows and the onion furrows into ridges. The height of each soil cultivation shall be determined according to the height of the growth of the pseudostem, about 3-4 cm. The soil shall be cultivated to the boundary between the leaf sheath and the leaf body. , from the beginning of autumn to harvest, the soil is generally cultivated 3-4 times.