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How to Grow Jicama: 9 Months, and Only the Root Is Edible

Jicama needs 150 to 270 frost-free days and a trellis. The vine, leaves, pods and seeds all contain rotenone and are genuinely poisonous.

By Zakaria 3 min read Save to Pinterest — opens Pinterest in a new tab
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Jicama is a legume grown for its root, and it comes with two hard constraints: a nine-month season, and the fact that everything except the root is poisonous.

Everything above ground is poisonous

The vine, leaves, flowers, pods and especially the seeds contain rotenone — a natural insecticide historically used as a fish poison and crop pesticide. The seeds are the most concentrated and have caused serious human poisonings.

Only the root tuber is food.

Two practical consequences: pinch the flowers off so pods never form, and bin or compost the top growth well away from anything you eat. If children or pets use the garden, growing it up a trellis rather than letting it sprawl keeps the foliage off the ground.

The season problem

What you get for your season
Frost-free daysRealistic outcome
180–270Full-sized roots. Subtropical conditions
150–180Usable but smaller roots
Under 150Vine, little root. Not worth the ground

Even with an eight-week indoor head start, a temperate-climate jicama is usually smaller than shop-bought. Worth growing for interest; not worth planning meals around.

Start indoors: soak seed 12–24 hours, sow an inch deep in deep pots eight weeks before last frost, germinate at 75–85 °F (one to three weeks).

Plant out only when nights stay above 60 °F. No frost tolerance at all, and a cold check early costs time you do not have.

Growing

  • Full sun, six to eight hours
  • Loose, deep, free-draining soil. Heavy clay gives small misshapen tubers
  • 8–12 inches apart, trellis in place before planting
  • Consistent water while the root swells — irregular watering cracks tubers and makes them woody

Do not feed it nitrogen

Jicama is a legume and fixes much of its own nitrogen through root bacteria.

Feed it and you get a spectacular twenty-foot vine and a disappointing root. This is the same mistake as feeding beans, with a more visible payoff for restraint.

Pinching flowers does two jobs

It increases the root. Energy that would go into seed goes into the tuber instead, and the difference is noticeable.

It prevents the pods. The pods and seeds are the most toxic part of the plant, so removing flowers keeps that material out of the garden entirely.

Check weekly once flowering starts and pinch buds out as they appear.

Harvest

When the vine yellows and dies back, or immediately before the first frost — whichever comes first. The root does not survive freezing in the ground.

Lift carefully with a fork; the tubers bruise. A root dug early is just smaller, not wasted, so an approaching frost is always sufficient reason to harvest even if the vine still looks green.

Peel the fibrous brown skin. The white flesh is crisp and faintly sweet, eaten raw in salads and slaws or cooked in stir-fries, where it holds its texture unusually well.

Step by step

Time
P210D
Cost
20
You need
Jicama seed, Compost, A sturdy trellis
Tools
Propagator or warm windowsill, Garden fork

  1. Count the season before you start

    Jicama needs 150 days at an absolute minimum and 180 to 270 for a full-sized root. Outside the subtropics it must be started indoors and will still produce smaller roots than commercially grown ones.

  2. Soak seed and start indoors

    Soak for 12 to 24 hours, then sow an inch deep in deep pots eight weeks before the last frost. Germination wants 75 to 85 F and takes one to three weeks.

  3. Plant out only when nights stay above 60 F

    It is a tropical legume with no frost tolerance. Planting into cold soil checks growth you cannot spare on a crop this long.

  4. Give full sun and well-drained soil

    Six to eight hours. Loose, deep, free-draining soil lets the root swell evenly; heavy clay produces misshapen small tubers.

  5. Space 8 to 12 inches apart with a trellis

    The vines reach 15 to 20 feet and need real support. Put the trellis in before planting rather than driving posts through roots later.

  6. Do not feed heavily with nitrogen

    Jicama is a legume and fixes much of its own nitrogen. Excess nitrogen gives you an enormous vine and a disappointing root.

  7. Water consistently through the season

    Steady moisture while the root swells. Irregular watering produces cracked and woody tubers.

  8. Pinch off the flowers

    Removing flower buds as they appear redirects energy from seed production into the root, and it noticeably increases size. It also prevents the poisonous pods forming.

  9. Harvest before the first frost

    Lift when the vine yellows and dies back, or when frost threatens, whichever comes first. The root does not survive freezing in the ground.

  10. Eat only the root, and discard everything else

    Peel the fibrous brown skin and eat the white flesh raw or cooked. The vine, leaves, pods and seeds contain rotenone and are poisonous — compost them well away from food crops or bin them.

Common questions

Is any part of the jicama plant poisonous?

Yes, and this is the most important thing to know before growing it. Only the root tuber is edible. The vine, leaves, flowers, seed pods and especially the seeds contain rotenone, a natural insecticide that is toxic to humans and was historically used as a fish poison and crop pesticide. The seeds are the most concentrated and have caused serious poisonings. Harvest the root, and bin or compost the top growth well away from anything you eat.

How long does jicama take to grow?

A hundred and fifty days at an absolute minimum, and 180 to 270 for a full-sized root, which puts it beyond most temperate seasons without starting indoors. Even with an eight-week head start, gardeners outside the subtropics generally harvest smaller roots than the ones sold in shops. It is a crop worth attempting for interest, but not one that reliably fills a store cupboard in a short season.

When should you harvest jicama?

When the vine yellows and dies back naturally, or immediately before the first frost — whichever comes first, since the root will not survive freezing in the ground. Lift carefully with a fork, as the tubers bruise. A root harvested early is simply smaller rather than unusable, so an approaching frost is always a good enough reason to dig, even if the vine still looks green.

Should you remove jicama flowers?

Yes. Pinching off flower buds as they form redirects the plant's energy from making seed into swelling the root, and it noticeably increases the size of the harvest. It has a second benefit worth more than the first: no flowers means no seed pods, and the pods and seeds are the most toxic parts of the plant, so removing the flowers keeps the poisonous material out of the garden entirely.

Can you grow jicama in a container?

It is possible but rarely satisfying. Jicama forms a large root that needs depth and loose soil to swell properly, so a container has to be very deep — at least eighteen inches and wider is better — and even then the root will be smaller than one grown in open ground. The vine still reaches fifteen feet and needs support regardless. If the ground is unsuitable, a large half-barrel is the realistic minimum.

Does jicama need a trellis?

Yes. The vines reach fifteen to twenty feet and will sprawl across everything nearby if left to it, shading other crops and making the flower-pinching job impossible. Put a sturdy trellis, fence or arch in place before planting rather than driving posts through the root zone later. Growing it vertically also keeps the foliage — which is the poisonous part — up off the ground and away from children and pets.

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