Onions are a popular, long-season, frost tolerant crop. Simple to grow from sets, and undemanding if you want to grow kitchen-sized bulbs. In mild areas with low rainfall, autumn planted onions may be more reliable. Onions can be oval or cylindrical in shape, with red, white, or golden brown skin. Long Day (Northern) Onion cultivars thrive in the northern latitudes, while short day types thrive in southern climates. Day neutral cultivars while will thrive in either climate. Organic and heirloom cultivars are available.

Ideal Location- Onions prefer an open sunny site but will tolerate a little shade. Autumn sown plants need full sun and must have good drainage. Onions look good around other crops but dislike being crowded. No soil treatment is needed if the soil was improved by a previous crop. If not use a low-fertility soil improver depending soil conditions. The ideal pH is 6-7.

Seed to Harvest- Spring sown seed: 20-24 weeks, autumn sown seeds: 42 weeks, spring sown sets: 18-20 weeks, and autumn sown sets: 36-38 weeks.

Cultivation- The minimum germination temperature is 45F(7C).

Seed under cover- Sow in trays or cell packs in February or March. Harden off and plant outside when 4in (10cm) tall. Multi-sowing: 6 seeds per cell and do not thin out.

Seed outside: Station-sow several seeds per section, as soon as soil is warm enough, usually by April. Thin to one seedling, leave several seedlings if multi-sowing.

Sets- Plant sets in March/April. They need a period of cold to initiate root formation, so plant as early as possible once soil is workable. Push sets into the soil so just the tips are visible, pointed end upward.

The above is for late summer harvest. If sowning in autumn for early summer crop the timing to suit geographical location is critical to ensure seedlings will survive the winter but not bolt in spring. A rule of thumb is to sow in the 2nd week of August in northern climates and the 4th week of August in warm areas.

Spacing- Bulb size is influenced by spacing. For medium sized bulbs- 1 ½ x 12in (4x30cm), for larger bulbs 4 x 12in (10x30cm). Block planting 4-6 in (10-15cm). Multi-sown: 10in (25cm)

Plant Care– Hand weed very carefully as roots are shallow. In spring apply an organic nitrogen fertilizer to overwintered onions if required.

Problems- Onion Fly, onion thrips, onion downy mildew, onion neck rot, onion white rot, and bolting ( a condition caused by fluctuating weather, which red cultivars are particularly susceptible.

Harvesting- Harvest to eat when bulbs are large enough. When onions stop growing the leaves turn brown and fall over. Dig or pull bulbs gently from the ground. Do not bruise the skin as this will reduce the shelf live considerably. Summer harvests can be stored in cool dry locations and can be stored for long periods of time., Thick necked onions should be used first as they do not store as well. Autumn sown onions should not be stored long-term.

Nutrients- Onions contain chromium, copper, manganese, potassium, phosphorus, folate, molybderum, tryptophan, dietary fiber, and vitamin B6, C