How to Grow Jicamas UK

Soil & Growing Conditions

Water: Moderate; seasonal rainfall, or high rainfall on sharply drained ground

Soil pH range

6.5 8

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Quick Facts

Factor	Value
Soil pH	6.5 - 8
Optimal growing temp	21-28°C
Time to harvest	150-270 days
Soil texture	Well-drained alluvial or volcanic soil
Drainage	Well-drained; does not tolerate waterlogging
Lifecycle	Frost-tender perennial vine grown as an annual for its single large tuber.

Harvest & Storage

When to pick: Tubers are lifted once they reach size. Useful Tropical Plants gives 150-270 days, or as little as 90 in ideal conditions. LEAVE THE PODS AND SEED: they carry rotenone.

Jicama through the season

The crop

Tubers as sold. This single swollen root is the only part of the plant that is food.

At market

Useful Tropical Plants gives the harvest at 150-270 days, or as little as 90 in ideal conditions.

In the ground

PROSEA gives an optimum daytime temperature of 21-28°C on well-drained alluvial or volcanic soil that must not waterlog.

A vigorous vine

The top growth is enormous relative to the root, which is why growers pinch out the flowers.

The leaf

Broad and three-lobed. A hand gives the scale.

The flower

Purple to lilac. Flowering and tuber growth are both triggered by shortening days, which is the crux for temperate growers.

Flower spike

Removing these as they appear is standard practice: seed production comes at the tuber's expense.

Close up

Handsome, and the reason the plant is sometimes grown ornamentally in the tropics.

DO NOT EAT THE PODS

Mature seeds carry 0.5-1.0% rotenone plus 0.5-1.0% rotenoids (PROSEA). Rotenone is a commercial insecticide. The tubers are free of it; the seeds are not.

Pods among the leaves

The foliage carries under 0.01% rotenone and rotenoids. Young pods must be thoroughly cooked; mature seed should not be eaten at all.

What the research guides add

Jicama is a long-season crop, and the two sources below put numbers on how long.

• For optimal harvests the plant needs about nine continuous months of frost-free weather (FGCU); Missouri Botanical Garden says the plant normally needs nine months of growth for a good-sized root, so in the St. Louis area tubers may be small by harvest. (Florida Gulf Coast University, Missouri Botanical Garden)
• It is a perennial vine that can be grown as an annual: sow in spring and harvest tubers in autumn just before the first frost. Start seed indoors in flats or peat pots 4 to 6 weeks before the last spring frost, and plant out in full sun when all danger of frost has passed and the ground is at least 50°F. (Missouri Botanical Garden)
• Any temperature below 50°F can ruin the tuber, and FGCU suggests digging the tubers as late as possible before frost affects the vine. Without frost, harvest 150 days or more after transplanting. (Florida Gulf Coast University)
• Safety: the vine, leaves, flowers, pods and seeds contain rotenone and are toxic (Missouri Botanical Garden); FGCU says not to eat the leaves, flowers or seeds. Only the tuber is eaten. (Missouri Botanical Garden, Florida Gulf Coast University)

Sources for this section

• Florida Gulf Coast University (Food Forest plant database): Jicama (Pachyrhizus erosus) Quick Facts
• Missouri Botanical Garden: Pachyrhizus erosus (Plant Finder)

Section researched and checked on 24 October 2026 by the SoilCommander Editorial Team. How we check facts: editorial policy.

References

1. Plant Resources of South-East Asia (PROSEA) - Pachyrhizus erosus (PROSEA)
2. Useful Tropical Plants (tropical.theferns.info) - Pachyrhizus erosus

2 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.