Onions are indeed a high yielding crop. You can harvest at least 20-23metric tonnes of onions from an acre and this is in just over 100 days after planting!
For each acre, you need a kilogramme of seeds.
How to grow onions
Start by preparing a nursery bed. To make it, dig deep into good loam soils and apply manure. Create a shelter over the bed and cover it with grass. Add artificial fertilisers. Cover the bed with grass and remove the grass when they germinate.
You need to apply pesticides on the young plants. Use a one-litre sprayer to avoid damaging the plants in the nursery.
After 4-5 weeks in the bed, they are ready for transplanting. Remove the shelter a week before transplanting.
The farm must be well-prepared now. You should have rows of one metre width on which to plant the onions, with 20 plants per square metre. The length of the rows is not so important though. Transplant in the evening or early morning.
Use your fingers to dig holes for the plant and push them in, then apply a little DAP.
After two weeks, apply calcium ammonium nitrate, then apply NPK after another two weeks.
They will be ready to harvest when the stems drop.