Five key points for raising onion seedlings: master the technique to grow strong seedlings
1. Choose superior varieties. In production, purple-skinned varieties such as Ziyu No. 1, Ziyu No. 2, Zixing, and Shuanghuanhong can be selected. These varieties have the characteristics of strong pungency, high yield, excellent quality, and suitability for export. These varieties generally yield about 5000 kg per mu, and high-yielding plots can reach 7500 kg per mu. 2...
1. Choose superior varieties
In production, purple-skinned varieties such as Ziyu No. 1, Ziyu No. 2, Zixing, and Shuanghuanhong can be selected. These varieties have the characteristics of strong pungency, high yield, excellent quality, and suitability for export. These varieties generally yield about 5000 kg per mu, and high-yielding plots can reach 7500 kg per mu.
2. Prepare the seedbed
The seedbed should be selected on plots with loose, fertile soil and strong water retention that have not grown onion, garlic, or similar vegetables within 2-3 years. Each mu of field for cultivation requires a seedbed area of about 35 sq m and a seeding rate of 0.5 kg. Before sowing, apply sufficient decomposed farmyard manure, plus 20-30 kg of a nitrogen, phosphorus, and potassium compound fertilizer, then plow, prepare the soil finely, make beds 1.5-2 m wide, water thoroughly, and wait to sow.
3. Sow at the right time
The timing of sowing directly affects the size of the seedlings, and thus ultimately affects onion yield. With early sowing, the seedling growth period is prolonged, causing an excessively large nutritional area, and the seedlings are prone to bolting; with late sowing, the seedlings are weak and small, with low cold tolerance, and are prone to dying during overwintering. Therefore, to achieve high yield, it is necessary to master the optimal sowing period. Use dry seeds for broadcast sowing, and after sowing cover with fine soil, just enough that the seeds are no longer visible. After covering with soil, each mu of seedbed can be sprayed with 100 ml of 33% pendimethalin to prevent and control weeds in the seedbed.
4. Seedling stage management
The central goal of seedling stage management is to cultivate strong seedlings. After sowing, cover the bed surface with a layer of wheat straw, which helps retain moisture, prevent high temperatures, and prevent rain. Before emergence, the soil should be kept moist at all times. When about 60% of the seedlings have emerged on the seedbed, the covering can be removed, and water should be sprinkled promptly according to weather conditions to prevent the seedbed from crusting, and a small amount of urea should be applied along with watering. Regulate fertilizer and water to cultivate strong seedlings of the right age. It is necessary both to prevent the seedlings from growing too large and causing early bolting, and to avoid the seedlings growing thin and weak, which affects overwintering. Generally, when onion seedlings grow to 4 true leaves, a plant height of 20-25 cm, and a leaf sheath diameter of 6-7 mm, they can be transplanted.
5. Transplant at the right time
When transplanting, the onion seedlings should be separated according to size for transplanting so that they grow uniformly, and large seedlings with a leaf sheath diameter exceeding 8 mm, as well as weak small seedlings below 3 mm and diseased seedlings, should be removed. Transplanting requires an average daily temperature of 4°C-5°C. Because onions take about 30 days from transplanting to resuming growth, it is necessary before severe cold arrives to promote good root growth and development and prevent soil freezing and heaving from causing seedling death. The transplanting density requires a row spacing of 20 cm and a plant spacing of 15 cm, and the transplanting depth should preferably not bury the five-branch crown. After transplanting, water to promote the survival of the onion seedlings. Never use flood irrigation, which causes soil crusting and is unfavorable for the rapid resumption of growth of the onions.