Pay attention to five points in raising onion seedlings.

First, the superior varieties can be selected in production, such as Ziyu No. 1, Ziyu No. 2, Zixing, Shuanghuanhong and so on. These varieties have the characteristics of strong spicy taste, high yield, good quality and suitable for export. These varieties generally have a yield of about 5000 kg per mu, and the yield of high-yield plots can reach 7500 kg per mu. Second, to prepare the seedbed, we should choose the land with loose soil, fertile soil, strong water retention and no onion or garlic vegetables in 2-3 years. Each mu of cultivated field requires a seedbed area of about 35 square meters and a seed consumption of 0.5 kg. Apply rotten farm manure before sowing, then add 20-30kg ternary compound fertilizer of nitrogen, phosphorus and potassium, then ploughing and fine soil preparation to make a bed 1.5-2 meters wide, watered thoroughly, to be sown. Third, the appropriate sowing time directly affects the size of seedlings sooner or later, which ultimately affects the yield of onions. Early sowing will prolong the growth period of seedlings, resulting in too large nutritional area and easy bolting of seedlings, while late sowing will lead to weak seedlings and low cold tolerance. Overwintering is prone to dead seedlings. Therefore, in order to achieve high yield, it is necessary to master the best sowing time. Dry seeds are used to sow and cover fine soil after sowing, so that no seeds should be seen. After covering the soil, 33% of the herbicide per mu of the seedbed can be sprayed with 100ml spray to prevent weeds from the seedbed. Fourth, the center of seedling management is to cultivate strong seedlings as the main goal. After sowing, cover the border with a layer of wheat straw, which is beneficial to moisturizing, high temperature and rain protection. The soil should always be kept moist before emergence. When about 60% of the seedlings grow on the seedling bed, the mulch can be removed, and the mulch can be sprinkled in time according to the weather conditions to prevent the hardening of the seedling bed. And combined with watering to apply a small amount of urea. The healthy seedlings of suitable age were cultivated by the regulation of fertilizer and water. It is not only necessary to prevent the seedlings from growing too large, causing early bolting, but also to avoid the weak growth of the seedlings and affect the overwintering. Generally, onion seedlings can be planted when they grow to 4 true leaves, with a plant height of 20-25 cm and a leaf sheath diameter of 6-7 mm. 5. when planting and planting at the right time, the onion seedlings should be transplanted separately according to the size of the onion seedlings, so that their growth is consistent, and the large seedlings with a leaf sheath diameter of more than 8 mm and weak seedlings and diseased seedlings with a diameter of less than 3 mm should be removed. Planting requires a daily average temperature of 4 ℃-5 ℃. Since it takes about 30 days from planting to resuming growth of onion, it is necessary to promote the root system to grow well before the severe cold, so as to prevent the dead seedlings caused by freezing and lifting roots in the soil. The planting density requires a row spacing of 20 cm and a plant spacing of 15 cm, and the planting depth is better not to bury pentagonal strands. Watering after planting to promote the survival of onion seedlings, do not flood irrigation, resulting in soil consolidation, is not conducive to the rapid recovery of onion growth.