Onions are a well-known vegetable, and red onions are a variety of onions harvested typically from late May to early June. Let's talk about the cultivation techniques for high-yield red onions.
Cultivation Techniques for High-Yield Red Onions
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Sowing: Choose fertile, loose, and water-retentive soil for full-layer fertilization. Apply 3-4 tons of decomposed sheep manure, 5 kg of urea, and 25 kg of calcium superphosphate per mu. After fertilization, perform shallow plowing and fine raking to create flat beds. Sow the prepared seeds evenly or broadcast them with sand. The seeding rate is about 5 kg per mu, with a depth of 0.5-1 cm. Keep the soil moist before seedlings emerge to prevent soil surface compaction, and cover the beds with shade nets.
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Transplanting:
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Seedling Selection: Suitable seedlings for transplanting should weigh 5-6 grams each, with stem thickness of 0.6-0.9 cm, height below 20 cm, and 3-4 true leaves. Before planting, strictly grade and select seedlings, eliminate elongated, stunted, diseased, bolting-prone, and tillering seedlings. Plant robust seedlings in graded rows and manage them separately.
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Transplanting Time: Generally from October 10th to 15th. Early transplanting may lead to bolting and excessive bulb growth, while late transplanting may result in inadequate root development, shorter growth period before winter, decreased cold tolerance, and increased risk of winter death.
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Planting Density: Determine the planting density based on the variety's growth period, maturity, soil fertility, and water and fertilizer conditions. The suitable row spacing for planting red onions is 17 cm × 8-10 cm, with 36,000 to 42,000 plants per mu.
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Planting Depth: Onions are suitable for shallow planting, with an appropriate depth of 3-4 cm.
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Field Management:
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Weeding: From transplanting to wintering, growth is slow, temperatures are low, and autumn rains are abundant. Watering should be controlled appropriately, with main emphasis on cultivating to retain moisture (preferably using manual hoes, promoting root development, with a depth of 3-4 cm, cultivating two to three times from seedling emergence to bulb swelling).
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Fertilization: In mid-March of the following year, combine with irrigation to fertilize once with 5 kg of urea and 15-20 kg of triple superphosphate or calcium superphosphate per mu to promote regrowth. In late April, when leaf growth is vigorous and bulbs begin to swell, a second fertilization should be applied with 8-10 kg of potassium dihydrogen phosphate and 5-10 kg of urea per mu.
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Irrigation: In mid-March, onion seedlings enter the regrowth stage. At this time, watering should not be too frequent or excessive. In early spring with low temperatures, cultivation should be intensified, and soil moisture should be maintained by loosening the soil manually to increase soil temperature and ensure the soil remains moist. In April, during the vigorous leaf growth stage, irrigate once. When the bulb diameter reaches about 2.5 cm, irrigate again, and then suppress leaf growth after bulb swelling to promote nutrient transport to the leaf sheath base. Ten to fifteen days after bulb swelling begins, irrigation should be frequent, with watering 3 to 4 times, keeping the soil moist. Watering is preferably done in the morning or evening. Stop watering 7 to 8 days before harvest to reduce bulb moisture content and increase bulb storage resistance.
Summary
The cultivation techniques outlined above can help achieve high yields of red onions. With their long growth period, high yield, good quality, and wide adaptability, red onions are an excellent vegetable variety.
