edenhana

Onion

A slow, long-season crop usually sown in autumn or late winter; leave bulbs to dry in the sun for a week after lifting so they store well.

Sun
full sun
Water
moderate
Spacing
10cm
Harvest
Ready in 150-200 days
Difficulty
intermediate
Grows in
Whangārei / Northland, Auckland, Hamilton / Waikato, Tauranga / Bay of Plenty, Gisborne, Napier / Hawke's Bay, New Plymouth / Taranaki, Palmerston North / Manawatū-Whanganui, Wellington, Nelson, Tasman, Blenheim / Marlborough, West Coast, Christchurch / Canterbury, Dunedin / Otago, Invercargill / Southland
Expected yield
1 bulb per plant
Cost to grow
~$8 NZD
Grocery value
~$35 NZD
Companion plants
Broccoli, Cabbages, Lettuces, Strawberries, Tomatoes, Beetroot
Plants to avoid nearby
Beans, Peas
Common diseases
White rot, Downy mildew
Common pests
Onion thrips

When to plant by region

In Whangārei / Northland, Auckland, Tauranga / Bay of Plenty, Gisborne and Napier / Hawke's Bay: March-May and August-September. In Hamilton / Waikato, New Plymouth / Taranaki, Palmerston North / Manawatū-Whanganui, Wellington, Nelson and Tasman: April-May and August. In Blenheim / Marlborough, West Coast, Christchurch / Canterbury, Dunedin / Otago and Invercargill / Southland: April and August.

Growing stages

  1. Germination & sowing

    • A slow crop to germinate, usually sown in autumn or late winter
    • Keep the soil surface moist while seed germinates, seedlings are fine and dry out easily
    • Onion thrips can target young seedlings in warm, dry spells

  2. Seedling & establishment

    • Thin seedlings to give bulbs room to develop at their proper 10cm spacing
    • Downy mildew can appear on leaves in damp, still conditions
    • Weeds compete strongly with onion's narrow leaves, so keep beds clear

  3. Bulb development

    • White rot can affect bulbs in the soil, avoid planting where alliums have grown recently
    • Onion thrips can build up on foliage as bulbs swell
    • Full sun and moderate, even watering needed for good bulb size

  4. Harvest150-200 days from sowing

    • Ready from about 150-200 days, once foliage yellows and falls over
    • Leave bulbs to dry in the sun for a week after lifting so they store well
    • White rot shows as soft bulb rot at this stage, discard affected bulbs rather than storing them

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