How to Grow Yacons
On this page
Yacon needs a frost-free growing season of at least seven months and grows best between 18°C and 25°C, tolerating summer heat up to 40°C if it's kept well watered — but its foliage is frost-tender, so start rhizome divisions indoors about two months before your local last-frost date and set out transplants once they're 15-30cm tall with three or four sets of leaves.
The short answer
- 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
Quick Facts
At a Glance
Diseases
Pests
Soil & Growing Conditions
Growth Stages
Harvest & Storage
Plan your Yacons planting
Timing for Yacons follows soil temperature and frost, not the calendar date. The Global vegetable planting calendar explains the method. 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.
Sources
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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.
These 3 sources are specific to this region. The full list of 3 sources behind this guide (Cultivariable, Maine Organic Farmers and Gardeners Association (MOFGA), Useful Temperate Plants) is in the references of our UK guide to yacon; they describe the plant itself, which is the same wherever it grows.
Frequently Asked Questions
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
This page gives you the thresholds; the planner turns them into your own calendar. It works from what you can observe and measure in your garden rather than from dates written for somebody else’s latitude.
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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 international horticultural research and extension sources. 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
Related guides
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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.