How to Grow Ocas Canada

By the SoilCommander Editorial Team, under the guidance of Nitin Sharma, Co-Founder · · How we check our facts

On this page
  1. Oca (Oxalis tuberosa)
  2. Quick Facts
  3. At a Glance
  4. Diseases
  5. Pests
  6. Growth Stages
  7. Harvest & Storage
  8. Plan your Ocas planting
  9. Growing Oca in another region
  10. Sources
  11. Frequently Asked Questions

Oca needs a cool summer to crop well: yields suffer once daytime highs regularly exceed 29°C, even in a garden mild enough for it to survive winter. It's frost-tender — hardy only to about -7°C to -4°C — so it's grown as an annual, with whole tubers planted 5–7 cm deep after the last frost.

Core growing advice on this page is checked against named horticultural sources — see References.

Oca (Oxalis tuberosa)

Oca (Oxalis tuberosa) plants in flower, a bushy border planting — “Kluse - Oxalis tuberosa 12 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.

2 sources cited · Verified

Quick Facts

Oca (Oxalis tuberosa) plants in flower, a bushy border planting — “Kluse - Oxalis tuberosa 12 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
“Kluse - Oxalis tuberosa 12 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
Factor Value
Drainage Loose, light, well-drained (Cultivariable); RHS: loam/sand, well-drained.
Lifecycle Tuberous, short-day perennial grown as an annual crop. Cultivariable notes it survives to USDA zone 9a (20-25°F minimum) but most of that zone runs too hot in summer for good tuber yields.
Edible parts tubers
Documented problems 4 diseases, 4 pests

At a Glance

A cluster of harvested oca tubers among dying foliage — “Kluse - Oxalis tuberosa 17 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
“Kluse - Oxalis tuberosa 17 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
Oxalis tuberosa Oca Wet rot / stem rot Oca virus diseases (Pap… Oca decline (symptom co… Bacterial soft rot (oca… Tarnished plant bug Wireworms Vine weevil Voles DISEASES PESTS

Diseases

A dense mat of oca foliage in a garden bed — “Kluse - Oxalis tuberosa 09 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
“Kluse - Oxalis tuberosa 09 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
Wet rot / stem rot
moderate

Choanephora cucurbitarum

Water-soaked wet rot with white silky mycelium

Named by Cultivariable: lower stems blacken and soften.

Oca virus diseases (Papaya mosaic virus and unidentified potyviruses)
low

Named by Cultivariable in some varieties, typically mild in impact; RHS's UK conservatory-context page reports the crop as generally disease-free, a genuine difference in growing context kept honest rather than merged.

Oca decline (symptom complex: knobbly tubers, early sprouting, reduced yields, fasciation)
low

A named symptom complex from Cultivariable: knobbly tubers, early sprouting, reduced yields, and fasciation.

Bacterial soft rot (oca tubers, causal agent not yet confirmed)
moderate

Named by Cultivariable affecting tubers; no specific bacterium identified.

Pests

Oca tubers freshly dug with roots and stems still attached — “Kluse - Oxalis tuberosa 22 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
“Kluse - Oxalis tuberosa 22 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
Tarnished plant bug
low

Lygus lineolaris

Named by Cultivariable as targeting flowers, mainly a concern for breeders rather than tuber yield.

Wireworms
low

Elateridae (click beetle larvae, various spp.)

Named by Cultivariable as causing mostly cosmetic tuber damage, rarely a serious problem.

Vine weevil
low

Otiorhynchus sulcatus

Named by RHS as the main UK risk for container/conservatory-grown plants.

Voles
high

Microtus spp. / Arvicola spp.

Named by Cultivariable as the most damaging pest, especially at harvest time when tubers are abundant underground.

Growth Stages

Close-up of oca clover-like trifoliate leaves — “Kluse - Oxalis tuberosa 10 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
“Kluse - Oxalis tuberosa 10 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
Stage BBCH Notes
Planting 0 Cultivariable: plant whole tubers 2-3in deep, 18in spacing between plants, 24-48in between rows for good air circulation; plant after the final frost, through August in cool climates. RHS: separate and replant tubers in autumn or spring.
Vegetative growth 3 Cultivariable: performs best in full sun where summer highs stay below 85°F with cool nights; give partial shade in hotter spells. Loose, light soil with added compost or organic fertiliser supports easy tuber harvest later.
Short-day tuber initiation 4 Cultivariable: tuber formation only begins once day length drops to 12 hours or less, starting after the autumn equinox (22-23 September) -- around six weeks of short days is needed before a reasonable harvest is possible.
Harvest 8 Cultivariable: harvest no earlier than early November, with the third week of November giving roughly 80% of potential yield; loose soil makes lifting the tubers easier and reduces damage.

Harvest & Storage

Freshly harvested oca tubers, pink and red, lying on soil — “Kluse - Oxalis tuberosa 19 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.
“Kluse - Oxalis tuberosa 19 ies” by Frank Vincentz is licensed under CC BY-SA 3.0.

When to pick: Cultivariable: harvest no earlier than early November -- tuber formation only begins after the autumn equinox once days shorten to 12 hours or less, so a third-week-of-November harvest captures roughly 80% of potential yield.

Storage

40°F/4°C at 90%+ humidity gives storage life over a year (Cultivariable); flavour mellows and loses acidity over 4-6 weeks if stored at room temperature instead.

Plan your Ocas planting

When to sow and plant Ocas depends on your own frost dates. Check the Canada vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Oca in another region

Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.

Sources

The full list of 2 sources behind this guide (Cultivariable (specialist Andean roots and tubers breeder/grower resource), Royal Horticultural Society) is in the references of our UK guide to oca; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

What problems affect oca?

Our data links 4 diseases and 4 pests to this crop. See the sections above for each one and how to manage it.

Plan next season before the problems start

Short-season growing is arithmetic before it is technique: days to maturity against frost-free days decides what will finish at all. The Canada Garden Planner does that subtraction for your region before you sow.

Get the Canada Garden Planner →

Instant PDF download · Written for Canadian growing conditions

SoilCommander Editorial Team — under the guidance of Nitin Sharma, Co-Founder

Every growing guide is checked against RHS, USDA Cooperative Extension, and other named horticultural authorities before publishing. How we check our facts.

How this guide is put together

The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against Canadian hardiness-zone and frost-date data, with provincial agriculture and university extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.

Vegetable Growing Guides Canada

Crops With the Same Problems

Last verified 2026-09-04

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