How to Grow Yacons UK
On this page
In the UK, yacon goes in the ground early April to early May.
Timing is the decision that matters most in the UK: sowing early April, and that same window applies across all 4 regions covered here.
The short answer
- Plant
- Early April to early May
- Site
- soil pH 5.5–6.5
- Biggest risk
- Powdery mildew
Core growing advice on this page is checked against named horticultural sources — see References.
Yacon (Smallanthus sonchifolius)
3 sources cited · Verified
When to Plant Yacons in the UK
When to plant yacons in the UK: in Southern England, sow early April to early May. Find your area in the table below.
Quick Facts
At a Glance
Soil & Growing Conditions
Growth Stages
Harvest & Storage
Diseases
Pests
Yacon, the Andean Apple-Pear Root
Plan your Yacons planting
When to sow and plant Yacons depends on your own frost dates. Check the UK vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Yacon in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
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 65-77°F; tolerates heat to 104°F 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.
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Grown from the tightly bunched RHIZOMES around the base of the stalks, not from the edible tubers: break away each rhizome, or cut it into pieces each with at least one growing point, and plant that. Sprouting rhizomes indoors ahead of planting out gives earlier establishment and better yields; dormant rhizomes can go out a week or two before frost-tender sprouted plants. Space 2ft apart at minimum, 3ft each way is better. Prefers deeply worked soil with ample humus and only moderate fertility (not high nitrogen), plus steady water, which gives larger tubers. Literature quotes six to seven months to maturity, but a good crop was taken in a cool four-month Maine season. Young plants are quite frost-tender, yet the underground parts are IMPROVED by a light frost on the top growth. Lift with a broadfork rather than a spading fork to avoid breaking the brittle tubers. Store eating tubers in a tight-lidded 5-gallon bucket so they do not wither, and keep seed rhizomes in an open bin in the dampest corner of the root cellar. Once established, yacon is remarkably resilient and pest-free.
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Mirrors FAO Ecocrop. Fetched and parsed directly for the numeric soil pH range.
3 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 yacon 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 yacon?
Sow early April to early May.
What soil pH does yacon need?
A pH of about 5.5–6.5. 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 yacon?
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
How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against RHS and Met Office guidance. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
Related Problem Guides
Last verified 2026-09-02
Plan Yacons by month
The months this guide gives for sowing or planting, each with the full list of jobs for that month in the UK:
More from the same group (roots & tubers):
Growing advice for your part of the UK
Timing and conditions change a lot inside one country. These guides cover frost dates and growing seasons region by region.
Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Keep going
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.