Key Points of Onion Cultivation: Full-Cycle Management from Seedling Raising to Harvest

Onion is a common biennial allium vegetable, with the swollen bulb as the edible part; it is highly adaptable and stores and ships well. According to bulb skin color, it can be divided into yellow, purple and white types, each with slight differences in maturity and flavor, so choose varieties according to local climate and market demand. Note that onion seedlings readily complete vernalization after exposure to low temperatures, leading to premature bolting the following year, so control of sowing time and seedling age is crucial.

For growing onions, choose flat land with convenient drainage and irrigation and loose, fertile sandy loam soil, and avoid continuous cropping with allium crops. When raising seedlings, prepare the soil finely and sow thinly at an appropriate rate to grow strong seedlings with thick stems and leaves; when the seedlings reach a suitable size, transplant them with soil attached, with the depth set so that the base of the bulb is covered but the growing point is not buried.

After transplanting, water once to help the roots recover; once the bulb swelling stage begins, water and nutrient needs increase, so keep the soil moist and apply a balanced fertilizer along with watering. In the middle and late growth stages, gradually reduce watering and drain water promptly after rain to prevent bulb rot; also watch for common pests and diseases such as downy mildew, purple blotch and onion thrips, and achieve early detection and early control.

Harvest when most plants have yellowed leaves and the false stem has softened and fallen over; after harvest, dry them in the field for a few days, and store once the outer skin is dry, which will noticeably improve storability. Overall, by managing variety selection and seedling raising, water and fertilizer management, and harvest timing well, onion bulbs can grow evenly and firmly, and the planting benefits will be more assured.