How to Grow Onions? A Detailed Guide to Planting Methods and Techniques

The first step in growing onions is to select a good cultivar; the second step is to prepare the beds and apply fertilizer, first plowing and fertilizing before sowing, then sowing and raising seedlings at the right time; the third step is transplanting, with the transplanting time for film-mulched fields around the Start of Winter and for non-mulched fields around Frost's Descent; the last step is field management.

The following are the sowing and seedling-raising matters for onions:

1. Sowing period and sowing rate

A suitable sowing period is the key to cultivating strong seedlings. Sowing too early produces large seedlings that tend to bolt after overwintering; sowing too late produces weak, small seedlings with poor cold resistance, small bulbs and low yield. Taking the Huang-Huai River basin as an example, the best sowing period is early to mid-September. A germination test is best carried out before sowing. Under normal conditions, the sowing rate per mu of seedling bed is 4-5kg; considering that 20% of weak and inferior seedlings need to be discarded and thinned out, the cultivation area should be 15 times that of the sowing seedling bed. If the germination rate is below 70%, the sowing rate should be increased as appropriate.

2. Bed preparation and fertilization

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

3. Control of underground pests

Apply 5kg of phorate per mu, evenly turning it into the soil while preparing the land, then harrow and level it finely.

4. Sowing

After the bed surface is leveled, water first, then broadcast the seeds evenly. Then cover with 0.8cm of nutrient soil to ensure uniform emergence. If after sowing the soil moisture cannot meet the requirements for emergence, water with a spray pot to promote emergence, or sow after sprouting. Soak the seeds in cold water for no more than 12 hours, wrap them in a damp cloth and place them in a cool place at 20~24°C to sprout, rinsing them with clean water once a day. When the seeds have just “broken white” (shown the white radicle), sow them in time without delay; if not sown in time, the growth of the radicle will cause inconvenience to the sowing work.

5. Emergence

After emergence, pay attention to the control of mildew and damping-off. The method is to use 150 grams per mu of 50% carbendazim or 40% chlorothalonil, mixed with 30-40kg of water for even spraying.

Generally, the yield per mu of early-maturing onions is 4500-5500kg, and that of mid-to-late-maturing varieties is 5000-5500kg. The benefit per mu is 3000-6000 yuan, making it a good planting project.