How to grow Oca

Oxalis tuberosa

🥕 Vegetable 🌱 Grown each year

Colourful, knobbly Andean tubers with a lemony crunch raw and a nutty taste roasted. Easy and blight-free, but tubers only swell as autumn days shorten.

At a glance: Sow late April to late May, harvest from mid November.

When to sow, plant and harvest

JanFebMarAprMayJunJulAugSepOctNovDec

Sow outdoors

Harvest

Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.

Growing Oca: what it needs

Light: Full sun · 6+ hours a day
Watering: Water in dry spells, especially as crops swell
Soil: Light, fertile soil
Spacing: 45 cm
In pots: Only in large containers
Feeding: A general fertiliser before planting
Harvest: About 200 days from sowing
Hardiness: USDA zones 3–9

Step by step

Late April – late May · 2 weeks after the last spring frost
Plant Tubers
Plant tubers 45 cm apart in rows.
14–28 days after “Plant Tubers” · Mid May – late May
Look for Shoots
Green shoots should be showing. Keep weeds down — these crops hate competition.
30–45 days after “Look for Shoots” · Mid June – late June
Earth Up
Draw soil up around the stems like potatoes once plants are 20 cm tall.
200–240 days after “Plant Tubers” · Mid November – late December
Harvest
Wait until frost kills the leaves (usually November), then leave the tubers in the ground two more weeks before lifting.
7–21 days after “Harvest” · Late November – early December
Dry and Store
Lay tubers in the sun for a few days to sweeten, then store in a cool, dark, frost-free place. Keep some to replant.