Botanical Name: Pachyrrhizus erosus
Common Names: Jicama (pronounced he'-cama) has a variety of common names including climbing yam bean; Mexican potato; Mexican Water Chestnut; Mexican turnip; cây củ đậu (Vietnam); seng kuang (Malay); di gwa (Chinese); kuzuimo (Japan); sinkamas (Filipino); man kaeo (Thai); sankalu (Hindi).
Plant Family: Fabaceae
Plant Description
Jicama is a vigorous, subtropical and tropical, climbing legume vine from South America. It has very pretty, big, blue pea flowers. Sadly the flowers should usually be removed as the bean pods and seeds are toxic, they also take a lot of vigour from the plant and reduce the harvest of tubers considerably. Let one plant go to seed for your next year's crop.
Even though this plant is an herbaceous perennial, it is usually grown as an annual, because the root tuber, the perennial part, is also the bit harvested. Jicama can be propagated from a tuber or seed. The plants die back in winter in cool climates but the tubers will shoot again in spring. The root of jicama develops swellings the size of a large turnip, (up to 5 per plant) under the surface of the ground.
Plant Height: Even though this vine can reach 2 - 6 m tall, it is usually pruned to 1 - 1.5 m as removing the flowers can double the yield of roots. In Mexico it is grown in fields and pruned with a machete.
Sow When
Jicama is frost tender and requires 9 months frost free for a good harvest of large tubers or to grow it commercially. It is worth growing in cooler areas that have at least 5 months frost free as it will still produce tubers, but they will be smaller.
Warm Temperate Areas: For areas that have at least 5 months frost free, start seed 8 to 10 weeks before the last spring frost. Bottom heat will be required as jicama needs a warm soil to germinate. Use either the top of a hot water system or a bottom heat propagator. The pots will need to be kept in a warm place. It is unsuitable for areas with a short growing season unless grown in a glasshouse.
Subtropical Areas: Sow the seed once the soil has warmed up in spring.
Tropical Areas: Sow all year in the tropics.
Planting Details
Seed Preparation: Soak the seed in warm water overnight to soften the seed coat and speed germination.
Planting Depth: Sow seed 5 cm deep.
Spacing: Space plants 20 - 25 cm apart in rows 60 - 90 cm apart.
Position: Full sun.
Soil Type: Jicama prefers a rich, moist, sandy loam soil with good drainage that is high in potassium.
Harvest
The tubers can be harvested from 4 months for small tubers, it takes 9 months for large tubers to develop. The seed pods and seeds are toxic and dangerous to eat. The pods contain rotenone, a toxic substance often used as an organic insecticide.
Eating: The sweet, juicy, crisp tubers are eaten raw or lightly cooked. To prepare, peel off the brown skin. The raw tubers taste like a cross between a water chestnut and an apple and do not discolour when cut. It is a great addition to salads and can be used as a crudité. It is also substituted for water chestnuts in stir-fry. In Mexico it is sliced thinly and sprinkled with salt, lemon juice and chilli sauce. As a food, jicama is low in calories, only 45 calories for one cup of cubed root.
New Crop Potential: As a new crop jicama has potential for small crop growers in warmer areas. We suggest you offer your crop to a local restaurateur, take some prepared pieces and explain how it can be used. Restaurants with a desire to provide fresh ingredients and a willingness to experiment will be at the leading edge of demand for this versatile crop. By selling to the end user you will get a higher value return. Selling at the local produce markets is a sure hit if you always offer free taste samples.
