Oca
Oxalis tuberosa
Also known asNew Zealand yam · Uqa · Apilla
Environment
The bounded range this crop tolerates.
Climate and zones
- USDA zones
- 7–10 (winter low around -18°C)
- Frost
- frost sensitive (dies at first frost)
- Season
- cool (spring/fall)
Growing systems
Root mass: moderate.
Growing media
| Medium | pH effect | Retention | Bacterial surface |
|---|---|---|---|
| Soil-based mix (Potting soil) | varies | high | high |
Nutrient demand by stage
NPK ratios are relative weights. EC targets shift through the plant's life.
| Stage | N | P | K | EC (mS/cm) |
|---|---|---|---|---|
| seedling | 2 | 1 | 1 | 1 |
| vegetative | 2 | 1 | 2 | 1.4 |
Aquaponics suitability
Not recommended
Fish waste alone doesn't supply enough of what this crop demands. Grows in hybrid systems with supplemental dosing, but expect active management.
Care notes
A specialty tuber crop with specific needs. Grow in media beds or large containers (15 L) of loose substrate. EC 1.2-1.8 mS/cm. pH 5.5-7.0. Temperature: 8–22°C (cool highland climate, best around 12–20°C; heat above 28°C suppresses tuber formation). Moderate light (DLI 14-22 mol/m2/day). The key challenge at temperate latitudes: oca only forms tubers once day length drops below about 12 hours (typically October-November in the northern hemisphere), yet the plant needs to be large and established by then to set a worthwhile crop. Start early (March-April) and grow through summer to build a big plant, then count on a long enough frost-free autumn for tubers to form. In mild-winter areas (zones 8 and up) this works; in cold climates frost kills the plant before tubers fully develop. Limiting daily light hours from August (covering the plants) is an experimental short-day workaround. Harvest after the foliage dies back from frost, digging carefully, and cure the tubers in sunlight for 1-2 weeks to sweeten them.