When to Plant Yam/Oca (New Zealand Yam) in Melbourne, Cool Temperate Guide

Plant September to October. Right now in October you can plant.

Also called oca, New Zealand yam.

Planting window
Plant tubers in spring once hard frosts ease, as the tops are frost tender. Tubers only swell as days shorten in autumn, so leave plants...
Days to harvest
about 17 weeks
Sunlight
Full sun to light shade. Tolerates more shade than most root crops.
Water needs
Keep well-watered during hot, dry periods. Oca is relatively drought-tolerant but...
Spacing
25cm apart, 45cm between rows
Soil pH
5.5-7.0

Published · Last reviewed · By GardenBuddy.au
Growing advice is reviewed by hand. Planting dates, current conditions and prices on this page update daily.

This Yam/Oca (New Zealand Yam) guide is written for the Cool Temperate zone, which takes in Melbourne, Hobart and Geelong. Somewhere else? Your postcode picks the right one.

Not your zone? Cairns Brisbane Sydney Canberra Alice Springs Perth

Also handy: will it frost this week? and what grows in shade.

Oca (also called New Zealand yam, uqa) is a South American tuber crop that produces colourful, waxy-skinned tubers in shades of red, orange, yellow, and white. It is a short-day tuberiser, meaning tuber formation only begins when day length drops below 12 hours. This makes it a unique autumn/winter crop in Australian gardens. Propagated from tubers, not seed.

See what grows now in your own postcode

Best Planting Window for Cool Temperate

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
- - - - - - - - P P - -

P = Planting window

Plant tubers in spring once hard frosts ease, as the tops are frost tender. Tubers only swell as days shorten in autumn, so leave plants until frost kills the tops before digging.

Want a nudge when it is Yam/Oca (New Zealand Yam) sowing time in Melbourne?

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This month in Cool Temperate

In October the Cool Temperate zone normally runs 19°C by day and 8°C overnight, with about 67 mm of rain over 9 or 10 wet days. The coldest October night on record across the zone was -3.0°C, so a late frost is not out of the question. Averages 1991 to 2026, 28 postcodes, SILO.

The full twelve months are on the Cool Temperate zone page.

How to Grow Yam/Oca (New Zealand Yam) in Cool Temperate Australia

When to Plant

Plant tubers in spring once hard frosts ease, as the tops are frost tender. Tubers only swell as days shorten in autumn, so leave plants until frost kills the tops before digging.

Soil
Free-draining soil rich in organic matter. Avoid waterlogging which causes tuber rot. Light, friable soil produces the cleanest tubers. Amend heavy soil with compost and coarse sand.
pH Range
5.5-7.0
Sunlight
Full sun to light shade. Tolerates more shade than most root crops.
Spacing
25cm apart, 45cm between rows
Watering
Keep well-watered during hot, dry periods. Oca is relatively drought-tolerant but consistent moisture improves yields. Reduce watering as foliage dies back in autumn/winter.

Companion plants: Garlic, Onion, Marigold

Avoid planting near: No known antagonisms, but keep away from other Oxalis species to prevent confusion with weeds

Grow before, grow after

Yam/Oca belongs with the root crops, the roots and alliums turn of a four turn bed rotation.

Grow before it
Fruiting crops (Tomato, Capsicum, Zucchini)
Grow after it
Legumes (Beans - Dwarf, Peas, Broad Beans)

Give the bed 3 turns before root crops go back in. Roots fork and go leafy in fresh manure, so they take the bed after the heavy feeders have used it.

Cool Temperate Growing Tips for Yam/Oca (New Zealand Yam)

Recommended Varieties

  • Red oca
  • Yellow oca
  • White oca
  • Sunset

Key Challenges

  • Early autumn frost may kill foliage before tubers reach full size
  • Short autumn tuber-formation window

Pro Tips

  • Melbourne gardeners can grow good oca with patience
  • Plant as early as possible after last frost to maximise the vegetative growth period
  • The more leaf area built up before autumn, the more energy available for tuber formation

Harvesting Yam/Oca (New Zealand Yam)

When ready: Foliage has completely died back (either from frost or natural senescence). This is typically 15-20 weeks after planting in temperate zones. Do NOT harvest early. Tubers only reach full size in the last 6-8 weeks as the plant channels energy from dying foliage into tuber growth.

How to harvest: Use a garden fork inserted 20-30cm from the plant base. Lift the entire clump gently. Tubers are attached to the plant base by thin stolons. Collect all tubers carefully as they break off easily. Save some of the best tubers for replanting next season.

Where to next

What yam/oca costs in the shops right now, retailer by retailer, updated daily.

Also worth sowing in the cool temperate zone this October: Sweet Corn, Beetroot, Rutabaga (Swede) and Asparagus Pea (Winged Bean).

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Common Questions About Yam/Oca (New Zealand Yam)

When do you plant yam/oca in Australia?

It depends on your climate zone, not the calendar month alone. Planting months by zone:

What else is yam/oca called?

Yam/oca is the usual Australian name. Overseas seed packets and recipes call it oca, New Zealand yam. Same plant, same growing advice.

Which zone am I in?

Type your postcode into the box under the heading and the page tells you, and links this crop in your own zone if it differs. Or look it up on the grow zone map. This page is the Cool Temperate zone, Melbourne is its reference city.