How to grow Jicama (Yam Bean) in Australia

Where to plant

Grow jicama in full sun in loose, well-drained soil, with a trellis or fence for the vines, which can climb 4 to 5 m. Loose soil lets the roots swell evenly. The seed needs very warm soil, about 21°C, to germinate.

Jicama needs about nine frost-free months for large roots. With at least five frost-free months it still makes roots, but they are smaller, so it is a gamble in cooler southern areas.

• North Queensland: sow in any month. Allow 6 to 9 months for good roots and lift them in dry weather.
• Darwin: sow from April to June, in the early dry season; the NT Government sowing calendar lists yam bean for this window, about 20 weeks to harvest.
• South East Queensland and the Northern Rivers: sow from September to November so the roots have the whole warm season to grow.
• Sydney, Melbourne and Adelaide: marginal. Sow in October or November in the warmest spot, once the soil is warm, and lift the roots before the cold. Expect small roots.
• Perth: sow in spring in the warmest spot, as for Adelaide.
• Canberra and Hobart: our calendar marks these as unsuitable, as the frost-free season is too short.

How to plant

1. Wait until the soil is warm, about 21°C. In warm temperate areas that usually means early summer.
2. Set up a trellis or fence for the vines.
3. Sow seed 20 to 30 mm deep and 15 to 30 cm apart along the support.
4. Keep the soil moist but not soggy until the seedlings appear.
5. Guide the young vines onto the trellis.

Watering and feeding

Water regularly through the growing season so the roots swell steadily. Ease off as harvest approaches, and lift the roots in dry weather where possible, as wet soil late in the season can rot them.

Jicama is a legume and needs little nitrogen. Dig in compost before sowing; a light feed with a fertiliser low in nitrogen during growth is plenty.

Pruning and care through the year

• Pinch off the flowers as they appear. This pushes the plant's energy into the root, and it also stops the poisonous seed pods forming.
• Keep children and pets away from the pods and seeds, which contain rotenone, a natural insecticide and fish poison.
• Tie in the vines as they climb.

Harvesting

Lift the roots when they are about 10 cm across, usually six to eight months after sowing in the subtropics, and always before frost. In the tropics, larger roots form if the plants are left longer. Dig carefully with a fork so the roots are not damaged.

Store whole roots dry in a cool place; they keep well for weeks to months, but very cold storage damages them. In the fridge they keep for up to about three weeks. Once cut, wrap and refrigerate and use within a week.

Growing in pots

Jicama can be grown in a pot at least 40 cm wide and deep with a trellis, in a loose potting mix. Roots in pots are smaller, but it is a way to try it in cooler areas, as the pot can sit in the warmest spot.

Using it

Peel the brown skin and eat the white flesh raw, sliced into sticks or salads, often with lime, chilli and salt, or cook it in stir-fries, where it stays crisp. Eat only the root. The seeds, pods, flowers and leaves are poisonous and must never be eaten.