How to grow Yacón

Smallanthus sonchifolius · yacon, Peruvian ground apple, Bolivian sunroot

Yacón (Smallanthus sonchifolius) — yacón is a tall Andean relative of the sunflower grown for its large, crisp, juicy storage roots. They are mildly sweet, with a taste often compared to apple and pear with a hint of celery, and are eaten raw like fruit or cooked. Plants usually reach 1.2–2 m, are killed back by frost and need a long season, so in cool climates they are started in pots and planted out after the last frost.

Checked against sources: October 3, 2026

Quick facts

Type	Vegetable
Family	Asteraceae
Light	Full sun
Soil pH	6–6.5
Frost	does not tolerate frost
Soil for sowing	from 10 °C
Germination	14 days
Seedlings ready	45 days
Sowing to harvest	210 days
Where it grows	Open ground

When to plant

Sow for seedlings about 8 weeks before planting out.

Plant out in open ground about a week after your last spring frost, once the soil is warm.

The first harvest comes about 210 days after the shoots appear.

Frost dates · When to plant

Care

Open ground

Stage	Watering	Temperature	Feeding
Seedlings	every 3 days	—	—
Growth	every 4 days	18…25 °C	potassium, at the start of the stage; potassium, 45 days into the stage
Harvest	—	—	—

Growing notes

Light

Full sun, sheltered from strong wind, which shreds the leaves.

Soil

Deep, fertile, free-draining soil rich in organic matter; it grows best in slightly acidic soil, about pH 6–6.5. It uses a lot of potassium but needs only moderate nitrogen.

Care

In spring, about two months before the last frost, pot up pieces of the crown — the cluster of small buds at the base of the old stems; the big edible roots cannot sprout. Keep the pots in a bright, cool, frost-free place, as warmth makes them leggy. After the last frost plant them 10 cm deep, buds up, 60–90 cm apart, in soil enriched with compost or well-rotted manure. Water generously — yacón copes with heat as long as it never dries out. Feed with potassium-rich fertiliser such as seaweed or wood ash; too much nitrogen reduces the root crop. Stake tall plants in windy places and watch for slugs. The roots keep swelling until late autumn, so lift the plants after frost has blackened the foliage, ideally at least five months after planting out; the roots are brittle, so dig wide around the plant. Leave the roots in a dry place under cover for two weeks to a month — they turn sweeter. Keep the crown, with stems cut to 5 cm, cool and frost-free (about 4 °C) to replant next spring. In a container, use one at least the size of half a barrel. Try a small amount first — the roots are rich in inulin, which can cause wind.

Sources

Figures checked against these sources.