Onions need full sun and will grow in most types of soil. Seed can be sown in trays or in-situ, although trays may be easier to manage. The young seedlings transplant well.
Set onions out in rows, with 15cm between the rows and 10cm between each plant in the row. Because onions have a shallow root system, they need space so that there isn’t competition for nutrients and water.
Good to know:
In addition to his main crop, food gardener Di-Di Hoffman also grows onions closer together in a small bed (1m²) for foliage production only. Young and tender onion leaves are a delicacy and are delicious in salads.
Water your onions well during the growing season and don’t let the soil dry out. Because the roots are shallow they don’t need deep watering. Check to see how deep the roots go and water to that depth. Keep the bed free of weeds. Onions have high nutrient requirements and should be fertilised at regular intervals.
Depending on the varieties, onions will be in the ground for five to six months before they are ready to harvest. From a planning perspective, you need to make sure that the space devoted to onions will not detract from other important spring and summer crops. Onions, generally, indicate when they are ready for harvest. Bulbs push themselves out of the ground and the top growth tends to fall over. Allow the bulbs to dry out before storing.