How to Grow Onions? A Detailed Guide to Growing the "Queen of Vegetables"

Onion is a common ingredient in our daily life, delicious when paired with all kinds of meat, and it has many benefits. It is a healthy vegetable with good market prospects. So, how do you grow onions? Let's take a look together.

I. Onion cultivars

1. Red-skinned onion

The bulb of the red-skinned onion is purplish red on the outside, with the fleshy scales slightly red or flesh-pink; the bulb is flat-globose or globose, about 10 cm in diameter. It stores and ships well, has a relatively short dormant period, and sprouts early. This onion variety is generally harvested from late May to early June and is cultivated throughout East China.

2. Yellow-skinned onion

The bulb of the yellow-skinned onion ranges from brass-colored to pale yellow, with fleshy scales that are slightly yellow and soft flesh, and a relatively strong pungency. The bulb is flat-round and slightly smaller than the red-skinned onion, 6-8 cm in diameter. It stores and ships well and yields less than the red-skinned onion, but its quality is better.

3. White-skinned onion

The bulb of the white-skinned onion is white, with white fleshy scales. The bulb is flat-globose, and some are tall-round or spindle-shaped. It is the smallest, about 5 cm in diameter, with excellent quality, but lower yield and weaker disease resistance. If sown too early in autumn in the Yangtze River Basin, it readily bolts prematurely, so it is not widely planted.

II. Growing conditions for onions

1. Temperature

Onions are highly adaptable to temperature. Seeds and bulbs can germinate slowly below 5 degrees, the optimum temperature for seedling growth is around 15 degrees, and vigorous seedlings can withstand low temperatures below 8 degrees. The bulb enlargement stage requires higher temperatures, but the temperature must not be too high, which would stop growth.

2. Light

Onion is a long-day crop, so it has relatively high light requirements. During the bulb enlargement stage and the bolting and flowering stage, it needs more than 14 hours of long daylight per day to grow normally. Under conditions of high temperature and short daylight, it will only grow leaves and not form bulbs, so it is easiest to grow in places with long daylight hours.

3. Water

Onions should be given sufficient water during the germination stage, the peak seedling growth stage, and the bulb enlargement stage, but water must be controlled during the seedling stage and before overwintering to prevent the seedlings from growing leggy. Onion seedlings are relatively drought-tolerant, and a humidity of around 60 is sufficient. If air humidity is too high, diseases easily occur, so do not water excessively either.

4. Soil

Onions are highly adaptable to soil, and ordinary soil can be used for planting, but fertile, loose, well-aerated neutral loam is best. There is no need to worry, as other soil types can also be used for planting. Onion roots have a relatively weak ability to absorb fertilizer, so high yields require sufficient nutrients and regular fertilization.

III. Seedling-raising techniques for onions

1. Sowing time

Onion planting requires choosing a suitable sowing time. If sown too early, the seedlings are large and readily bolt after overwintering; if sown late, the seedlings are weak, have poor cold resistance, and produce small bulbs and low yields. The best sowing time in the Yangtze River Basin is in early September.

2. Sowing rate

Under normal conditions, the sowing rate for onions is 4-5 kg per mu of seedling bed. It should not be too much or too little; plant at a reasonable density.

3. Making beds and fertilizing

The bed height is 1.4-1.5 m and the bed width is 27 cm. After leveling the bed surface, apply 15 kg of superphosphate per mu, and use 4 cubic meters per mu of thoroughly decomposed organic farmyard manure as base fertilizer. After emergence, broadcast quick-acting nitrogen fertilizer together with watering, applying 10 kg of urea per mu.

4. Sowing method

After leveling the bed surface, water first, then broadcast the seeds evenly. After sowing, cover with 0.8 cm of nutrient soil. If the soil moisture is poor after sowing, water with a watering can to promote emergence. You can also sow after pre-sprouting the seeds.

5. Disease control

After onion seedlings emerge, pay attention to the control of downy mildew and damping-off. Spraying with 50% carbendazim or 40% chlorothalonil is sufficient.

The above is the onion growing method summarized for you by Tuliu.com. We hope it can help growers.