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

Sow October to November. Right now in September it is out of season. The next sowing month is October.

Also called oca, New Zealand yam.

Published · Last reviewed · By Garden Buddy
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.

Planting Calendar for Cool Temperate

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

S = Seed Tray   T = Transplant   D = Direct Sow

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

When to Plant

Plant September-October after frost. Grow through spring and summer. Tubers form from March as days shorten. Harvest May-June. Frost kills foliage but tubers can survive light frost if well mulched.

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

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 September: Ginger, Sweet Corn, Chilli Peppers and Snow Peas.

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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:

Does yam/oca grow all year round in Melbourne?

No. In the Cool Temperate zone the planting months are Oct to Nov. Outside that window it either bolts, sulks or gets cut down by the weather.

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.