Yacon (Smallanthus sonchifolius)
1 sources cited · Verified
The short answer
- Site
- 6+ hours of sun, soil pH 6–6.5
- Biggest risk
- Cucumber mosaic virus
Yacons (Smallanthus sonchifolius) — perennial.
This crop carries an unusually heavy problem load: 3 diseases, 7 pests and 0 nutrient issues are documented for it, so most of the effort in growing it well goes into prevention.
Core growing advice on this page is checked against named horticultural and university-extension sources — see References.
Diseases
Pests
Quick Facts
At a Glance
Soil & Growing Conditions
Growth Stages
Harvest & Storage
Yacon, the Andean Apple-Pear Root
References
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A sunflower-family (Asteraceae) perennial from the Andean highlands, grown for crisp, juicy, mildly sweet storage roots (technically tuberous roots, not tubers) with a flavour resembling apple, pear and celery. Typically grows 4-5ft tall, up to 6.5-8ft in long-season climates. Prefers weakly acidic soil (pH 6.0-6.5) rich in organic matter, heavy potassium user, moderate nitrogen, low phosphorus. Likes plenty of water and is not drought tolerant. Requires a frost-free season of at least 7 months; optimum growth temperature 65-77F; tolerates heat to 104F with sufficient water but is vulnerable to frost. Needs wind protection as leaves shred easily. Propagated mainly by crown rhizome pieces (minimum half an ounce, two growing tips) or stem cuttings; seed propagation is possible but has poor germination without scarification. Flowering occurs 5-9 months after planting; storage roots mature over 6-8 months and continue growing until the plant enters senescence. Harvested from mid-October through November, or after frost damage, with a minimum of 5 months ground time for reasonable yield and 8 months for optimal yield; roots are worked free with a shovel angled beneath the plant. Post-harvest, roots are left for about a month to sweeten via increased fructose content. Pests: slugs, caterpillars, aphids, whiteflies, field mice/voles (late season), rabbits and deer browsing foliage; generally pest-resistant compared to related sunflower-family crops. Diseases: cucumber mosaic virus (a serious yield problem), common fungal mildews, and Rhizoctonia, which causes lesions and black rot under the storage root skin; a Yacon necrotic mottle virus causes leaf yellowing, mottling, twisting and malformation.
1 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.
Frequently Asked Questions
What soil pH do yacons need?
A pH of about 6–6.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect yacons?
Our data links 3 diseases and 7 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Almost everything on this page resolves to your own frost dates rather than the calendar — the last spring frost moves by roughly two months between zone 3 and zone 10. The USA Garden Planner works from your zone so the timing is already decided before the season starts.
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Last verified 2026-08-29
Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.