When to Plant Yacon in Cairns — Tropical Guide

Yacon

Photo: Wikimedia Commons

Yacon (Peruvian ground apple) is an unusual South American root crop producing large, sweet, crunchy tubers that can be eaten raw like fruit. It stores energy as fructooligosaccharides (FOS) rather than starch, making it very low calorie and prebiotic. The plant grows like a sunflower (1.5-2m tall), is virtually pest-free, and produces prolifically. Propagated from rhizomes, not seed.

How to Grow Yacon in Tropical Australia

When to Plant

Plant year-round in frost-free areas. Yacon is day-length neutral. Tuber formation occurs after flowering and top die-back (triggered by shorter days or drought stress).

Soil
Rich, friable, well-drained soil. Grows in a wide range of soils but crops best in deep, fertile loam with plenty of organic matter. Avoid waterlogged conditions.
pH Range
5.5-7.0
Sunlight
Full sun to light shade. Tolerates some shade but yields best in full sun.
Spacing
60cm apart, 90cm between rows
Watering
Water regularly during establishment and dry periods. Yacon is surprisingly drought-tolerant once established but yields more with consistent moisture. Reduce watering after the top growth dies back i

Companion plants: Sunflower, Corn, Jerusalem Artichoke

Avoid planting near: No known antagonisms

Tropical Growing Tips for Yacon

Recommended Varieties

  • Standard (limited named varieties available in Australia)
  • Any available yacon rhizomes

Key Challenges

  • May grow vegetatively for too long without tuberising well
  • Waterlogging in wet season

Pro Tips

  • Yacon grows vigorously in the tropics but may produce more foliage than tubers
  • Planting in the dry season can trigger earlier die-back and tuber maturation
  • Raised beds essential for drainage

Harvesting Yacon

When ready: Top growth withers and dies back naturally (triggered by shorter days and cooler temperatures). DO NOT harvest early - tubers continue to sweeten as the plant dies back. Wait until ALL foliage is completely dead. This typically takes 6-7 months from planting.

How to harvest: Cut dead stalks to ground level. Use a garden fork inserted 30-40cm from the base. Lift the entire clump carefully. Separate the two types of underground growth: (1) REDDISH RHIZOMES at the crown base - save for replanting; (2) LARGE BROWN TUBERS below - these are for eating. Handle tubers gently as skin is thin. Sun-dry tubers for a few days to sweeten further.

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