Sharing Experience in Winter Onion Cultivation

Onions are cold-tolerant and moisture-loving, widely adaptable, easy to grow, strongly resistant to insects, tolerant of storage and transport, high-yielding and economically rewarding, making them one of the more ideal varieties for winter vegetables. Onions taste sweet with a slight pungency, and are also one of the vegetables people enjoy eating. According to the experience of farmers in Yangchun City, using idle winter fields to grow onions generally gives a yield of 2000-2500 kg per mu, with high yields reaching over 3000 kg, and a output value of 3500-4000 yuan per mu. For high-yield winter onions, the following technical steps should be carried out carefully.  

1. Raising strong seedlings. Sowing and raising seedlings is best done from late September to mid-October. The seedling bed should preferably be loose, fertile sandy loam or new land with convenient drainage and irrigation that has not previously grown onions or garlic. Before sowing, prepare the soil finely, apply plenty of base fertilizer, and form level beds for sowing. Before sowing, soak the seeds in warm water for 24 hours, then dry them and mix with dry crushed soil for even broadcasting. Sow 70-75 grams per 0.1 mu of seedling bed. After sowing, cover the surface with fine soil, then cover with weeds to prevent rain wash and direct sun exposure. After covering with grass, water with diluted manure water, and scatter insect-prevention chemicals around the beds. Once the seedlings emerge, remove the covering weeds. During the seedling period, water with diluted decomposed manure water once every 5-6 days. After about 40 days of seedling stage, they can be transplanted.  2. Timely transplanting and sufficient base fertilizer. Onions should not be grown continuously on the same land. The planting site should preferably be land previously used for solanaceous fruits, melons and beans, or late-season rice, especially loose and fairly fertile sandy loam or newly reclaimed land. Generally, transplant in mid-November to early December so the seedlings grow rapidly before "Major Cold" and are not damaged by frost. Before transplanting, disinfect the soil with 25 kg of lime per mu, and use 1500 kg of high-quality farmyard manure as base fertilizer. Plant on raised beds with a bed surface width of 80-100 cm and a bed height of 25-30 cm. The soil layer on the bed surface should be loose, fine and level. The planting spacing is: plant spacing 10-12 cm, row spacing 14-16 cm, planting depth 2-3 cm, about 8000 plants per mu. After planting, water thoroughly to settle the roots and aid survival.  3. Strengthen field management.  1) Timely topdressing: 7 days after transplanting, apply once with thin human and livestock manure water; after another 7-8 days, apply once with burned soil or high-quality farmyard manure to promote rooting and enhance cold resistance. In the severe cold season, onion seedlings grow slowly, so topdressing may be paused. By late February of the following year, when the bulbs enter the swelling stage, 1-2 heavy fertilizer applications should be made, applying 10-12 kg of urea plus 5-6 kg of potassium sulfate per mu. In late March, when the bulbs swell rapidly, apply another 1250 kg of decomposed human manure per mu, and stop fertilizing 25 days before harvest.  2) Scientific water management: Onions like moisture but are prone to waterlogging. In the early stage, the seedlings are small and the temperature is relatively low, so water demand is small; keeping the bed soil moist is enough. After spring warms up, the temperature gradually rises, onions grow faster, and bulbs form in large numbers and enter the swelling stage, requiring more water, so water thoroughly. But when there is a lot of rain in spring, drain the ditches promptly to prevent water accumulation in the field. Stop watering 10 days before harvest to facilitate harvesting and avoid high water content in the bulbs that would make them less storable. 4. Timely harvest. When the plant leaves gradually turn yellow and the basal leaves begin to dry up, the onion heads have stopped growing and swelling, so they should be harvested promptly. At harvest, cut off the onion leaves and try not to damage the onion heads, to facilitate storage and transport.