How to raise seedlings when growing onions?

How to raise seedlings when growing onions? Netizens with experience in growing onions are also invited to help introduce that onions are widely planted everywhere, with the characteristics of low investment, high yield and easy management. it is one of the first choices for vegetable farmers to optimize their planting structure and develop efficient agriculture. Therefore, the farming network specially collates the seedling steps before onion planting, which are listed in detail below for netizens' reference. Step 1, select excellent onion varieties: onion varieties can be divided into yellow skin and red skin according to color. Different varieties have their own advantages, and the selection of varieties should be arranged scientifically according to local planting habits and market needs. Wampee varieties have the advantages of tender meat, sweet and spicy taste, resistance to storage and transportation, good quality, but slightly lower yield. You can choose onion No. 4, Golden Ball No. 3, etc.; Red skin can choose varieties with strong spicy taste and high yield, such as Zixing, Shuangqiu Red and so on. Step 2, the preparation of the onion nursery bed: the onion seedbed should choose the land with loose soil, fertile and strong water retention, and no onion or garlic vegetables have been planted in 2-3 years. Each mu of field needs a seedbed of 0.5 minutes (about 35 square meters) and a seed amount of 0.2 kg. Before sowing, it is necessary to apply fully rotten basic fertilizer, and then match the ternary compound fertilizer containing nitrogen, phosphorus and potassium. Each plot is spread according to 2-3 kilograms and ploughed, and then carefully prepared to make a 1.5-2-meter-wide border, watered thoroughly, and waiting for sowing. Step 3, determine the sowing time of onions: the sowing time of onions will directly affect the size of seedlings and ultimately affect the yield of onions. Early sowing, the seedling growth period is prolonged, resulting in too large nutritional area, seedlings easy to bolting; late sowing, weak seedlings, low cold tolerance, easy to die through the winter. Therefore, in order to achieve high yield, it is necessary to master the best sowing time. According to the production experience of vegetable farmers, the most suitable sowing time is 3 days before and after White Dew (early September). Use dry seeds to sow and cover fine soil after sowing to the extent that no seeds are seen. After covering the soil, 33% of the herbicide per mu of the seedbed can be sprayed with 100ml spray to control the weeds in the seedbed. Step 4, the management of onion seedling stage: the central task of seedling management is to cultivate strong seedlings of suitable age. Covering a layer of wheat straw or shade net on the border after sowing is beneficial to moisturizing, high temperature and rain protection, and 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 sprinkled in time according to the weather conditions to prevent the hardening of the seedling bed. 1% urea can be applied in combination with watering, and strong seedlings of the right age can be cultivated through fertilizer and water control. It is necessary to prevent onion seedlings from overgrowing and causing early bolting, but also to avoid weak seedling growth and affect overwintering. In general, onion seedlings can be planted when they reach 4 true leaves, plant height 20-25 cm and leaf sheath 6-7 mm in diameter. Step 5, the colonization of onion seedlings: when planting, they should be transplanted separately according to the size of onion seedlings, so that their growth is consistent, and remove large seedlings with a leaf sheath diameter of more than 8 mm and weak seedlings and diseased seedlings less than 3 mm. The colonization is generally completed from the end of October to the first ten days of November, and the average temperature is required to be 4-5 ℃. Since it takes about 30 days from planting to resuming growth of onions, it is necessary to promote the growth and development of the front roots of onions before the severe cold, so as to prevent the dead seedlings from freezing and lifting roots in the soil. The planting density is generally required to plant about 20,000 plants per mu, the row spacing is 20 × 15 cm, and the planting depth is better without burying pentagonal strands. Watering after planting to promote the survival of onion seedlings, do not irrigate the whole field, resulting in soil consolidation, not conducive to the growth of onions. How to plant onion and control of onion downy mildew with high yield