A Detailed Guide to Onion Planting Methods and Key Technical Points

Onions are mainly grown by sowing seed, and their seed-saving methods include the large bulb seed-saving method, the small bulb seed-saving method, the small plant seed-saving method, and the continuous seed-saving method from seed plants.

The detailed onion seed-saving methods are as follows:

Onion seed-saving methods

1. Large bulb seed-saving method

The large bulb seed-saving method is the seed-saving method adopted in most regions of the country. Sow in September to October of the first year, and the seedlings overwinter in the open field or in storage. In the summer of the second year, harvest the large bulbs, select superior individuals from them, and after 4 rounds of storage, eliminate diseased plants. Transplant to the field in September to November. In severe cold regions, plant the mother bulbs in the spring of the third year and harvest the seeds in June. From sowing to seed harvest takes about 21 to 23 months.

2. Small bulb seed-saving method

The small bulb seed-saving method is a method often used in spring-sowing regions. As soon as the soil thaws in early spring, sow directly and raise seedlings. In summer, the small bulbs mature; select and keep bulbs with a diameter of more than 3 cm. After storing them over winter, plant them in the second year to save seed. From sowing to harvest takes about 16 to 19 months. This shortens the seed-saving cycle and lowers costs, and it can be used to propagate seed for production, but because no selection for mature bulb traits has been carried out, the seed quality degenerates.

3. Small plant seed-saving method

The small plant seed-saving method is also called the non-bulbing seed-saving method. Sow in July to September of the first year; before winter the plants grow into large seedlings that meet the green-plant vernalization standard and pass through the vernalization stage, ensuring that the plants bolt and flower in the second year. The whole cycle is about 11 to 13 months, shortening the seed-saving cycle, but no bulb is formed, so the seed quality degenerates. At the same time, because of the inheritance of the premature bolting trait, continuing this for a long time will lead to failure in cultivating bulbs in production.

4. Continuous seed-saving method from seed plants

After using the large bulb method to collect seeds, several small bulbs form at the base of the seed plant. After harvesting and storing them, plant them in autumn. In dry regions they can also overwinter in place. After sprouting, the original single mother bulb becomes 3 to 4 mother bulbs. The next year, the number of flower stalks produced is the first-year seed harvest, and the second-year seed harvest lowers costs, shortens the seed-saving cycle, ensures seed quality, and also increases yield.

The sowing time of onions is one of the keys affecting their yield and quality, so sowing at the right time is very important.