Does a cook ever have enough onions? Pungent bulb onions are great and add flavour to any meal. I must say, we Zambians use onions in everything. As an agricultural farmer in Zambia, you need to tap into this need. So, if you’re thinking about growing onions on a large scale, then this article could help you make that decision.

How to grow onions

You can grow onions can from seeds, transplants (seedlings) or sets (small bulbs/onions).   Transplants are seedlings grown in the current season and sold in bunches. They form good bulbs quickly but are subject to diseases. Sets are immature bulbs grown the previous year and are the easiest to plant, the earliest to harvest and the least susceptible to diseases.

The main advantage to growing onions from seed is that seeds are much cheaper. Also, they have the potential to produce larger bulbs. But, they require a little more time and effort. You also need to grow seeds in a greenhouse first i.e. indoors under bright fluorescent lights. So if you want to plant directly in the garden, then opt for sets.

The planting process

Onions like cool weather in the early part of their growth, so plant them before it gets too hot. Choose a section with the least weeds. It has to be sunny with fertile and well-drained soil.

Plough the soil to at least 30 cm deep. Mix in a 3cm layer of mature compost and make beds. In between the beds, make a 10cm deep, V-shaped furrow.

Fill the bottom of the furrow with 3cm of rich compost or fertilizer, and then water the prepared furrow. Plant seedlings or sets 3 to 6 inches apart, depending on the plants’ mature size.

As the onions start to grow, you need to move the soil away from the top of the bulbs. Exposure to the air helps the papery skin firm up, preventing rot. Leave only the lowest part of the bulb in contact with the earth.

Harvesting your onions

Onions need a long growing season. It’s easy to harvest them by pulling them out of the ground. Once onion tops start to turn yellow, use the back of a rake to bend them over horizontally. A day or so later, the tops will turn brown. This is time to pull or dig the bulbs on a sunny day, and leave them to dry in the sun. The most important thing is to cure the bulbs. This means allowing them to air-dry for about a month with their tops on.

When the outer skins are thoroughly dry, wipe off any soil and remove the tops—unless you intend to braid them. Store in a cool, dry place; hang braided onions or those kept in mesh bags in an airy spot. Such dried bulbs will keep for about 4 months to 1 year.

Do this to prevent pests in future harvests

Onion root maggots eat onion roots and bulbs.Especially when the Zambian rainy season is in full swing. Also, rotting onions attract adult flies. So, rotate onions with other crops. Avoid planting onions continuously in the same place. Furthermore, planting late can help you avoid this pest. But if you plant now, you can use row covers which is when the egg-laying females are most active.

It’s important to keep areas near onions mowed to reduce the weedy habitat that onions prefer. Use a spinosad-based biological pesticide to control serious infestations. Pink root and several other soil borne diseases can cause onions to rot. Use resistant varieties, and grow all onions in well-drained sites.