Yacon (Smallanthus sonchifolius)
1 sources cited · Verified
The short answer
- Plant
- Early April to early May
- Site
- 6+ hours of sun, soil pH 6–6.5
- Biggest risk
- Cucumber mosaic virus
In the UK, yacons go in the ground early April to early May.
Yacons (Smallanthus sonchifolius) — perennial.
Timing is the decision that matters most in the UK: there are 4 separate regional sowing windows, ranging from early April in Southern England to early April in Scotland.
Core growing advice on this page is checked against named horticultural and university-extension sources — see References.
Regional Planting Calendar
Quick Facts
At a Glance
Soil & Growing Conditions
Growth Stages
Harvest & Storage
Diseases
Pests
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
When should I sow yacons in the UK?
In Southern England, from early April. In Scotland, wait until early April. Treat these as a guide rather than a fixed date — the governing rule is to sow only once frost risk has passed and temperatures are reliably warm enough.
When do I sow yacons?
Sow early April to early May.
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
Most of the advice on this page comes down to timing and spacing — sowing at the right moment, rotating beds, and giving plants enough airflow. The UK Garden Planner lays your plot out month by month so those decisions are already made before the season starts.
Get the UK Garden Planner →Instant PDF download · Written for UK growing conditions
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.