Onions can be grown from seed or sets (small bulbs). Sets are more costly, and there is a smaller range of cultivars available, but they are quick, reliable, and a good choice for beginners.
When to start: Early spring.
At their best: Midsummer.
Time to complete: 1 hour.
You will need: Onion sets, spade, horticultural grit for heavy soils, rake, string line.
Onions need good drainage, so add horticultural grit to heavier soils. Stretch a line of string between two pegs to make a straight row. Use a rake to form a shallow furrow, and plant the sets 6 in (15 cm) apart, with the tips protruding. Weed regularly, and water during dry spells.
Lift and dry
Onions are ready for harvesting in midsummer, when the leaves turn yellow and fold over. Lift them and leave them in a cool, airy place to dry out for a couple of weeks. Use any with thick necks right away, and store the others for later.