How to Grow Wasabis UK
On this page
In the UK, wasabi goes in the ground early November to mid December.
Timing is the decision that matters most in the UK: sowing early November, and that same window applies across all 4 regions covered here.
The short answer
- Plant
- Early November to mid December
- Biggest risk
- Phytophthora blight
Core growing advice on this page is checked against named horticultural sources — see References.
Wasabi (Eutrema japonicum)
2 sources cited · Verified
When to Plant Wasabis in the UK
When to plant wasabis in the UK: in Southern England, sow early November to mid December. Find your area in the table below.
| Region | Sow |
|---|---|
| Southern England | early November to mid December |
| Midlands | early November to mid December |
| Northern England | early November to mid December |
| Scotland | early November to mid December |
Southern England - detail & sources
NC State gives a specific late-fall-to-early-winter sowing window (needing about two months of cold to break dormancy) rather than UK-specific dates; this window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.
Midlands - detail & sources
NC State gives a specific late-fall-to-early-winter sowing window (needing about two months of cold to break dormancy) rather than UK-specific dates; this window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.
Northern England - detail & sources
NC State gives a specific late-fall-to-early-winter sowing window (needing about two months of cold to break dormancy) rather than UK-specific dates; this window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.
Scotland - detail & sources
NC State gives a specific late-fall-to-early-winter sowing window (needing about two months of cold to break dormancy) rather than UK-specific dates; this window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.
Quick Facts
| Factor | Value |
|---|---|
| Soil texture | clay, loam or sand; organic, loose, crumbly (NC State) |
| Drainage | well-drained |
| Lifecycle | herbaceous perennial |
| Edible parts | rhizome, leaves, flowers |
At a Glance
Soil & Growing Conditions
Water: moist, good drainage, tolerates occasional flooding (NC State)
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Seed preparation and sowing | 0 | Sow late fall to early winter; needs about two months of cold before sprouting. Soak seed overnight in distilled water first; plant 2in deep, one seed per hole, rows 2in apart (NC State). |
| Establishment | 3 | Dappled sunlight to deep shade; organic, loose, moist, well-drained soil at 46-70°F; container growing needs a shallow water pan (NC State). |
| Rhizome development | 4 | Rhizome develops slowly, taking up to three years to reach harvest size of 1 inch diameter (NC State). |
| Harvest | 8 | Pull the whole plant once the rhizome reaches 1 inch diameter; grate within 30 minutes of harvest for best flavour (NC State). |
Harvest & Storage
When to pick: Rhizomes take up to three years to reach a harvestable size of 1 inch in diameter. Harvest by pulling the whole plant; best flavour comes from grating the cleaned root within 30 minutes of harvest, though it can be kept refrigerated for a month (NC State).
Diseases
Pests
Wasabi, Seedling to Grated Rhizome
Plan your Wasabis planting
When to sow and plant Wasabis 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 Wasabi in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
References
-
Hardiness USDA zones 7a-10b. Light: dappled sunlight (shade through upper canopy) to deep shade (less than 2 hours direct sun). Soil: clay, loam or sand; pH acid, neutral or alkaline; good drainage with moist conditions, tolerates occasional flooding and wet soils; plant in organic, loose, crumbly soil, add coarse sand to improve drainage. Optimal growing temperature 46-70°F; native to mountainous riverbank environments similar to fern habitat. Best sown late fall to early winter, needing about two months of cold before sprouting; soak seed in distilled water overnight to soften the coat and speed germination; plant 2 inches deep, rows 2 inches apart, one seed per hole. Container growing: containers at least 10-12 inches deep and wide, set in a shallow water pan. Propagate by division, seed, or plantlets. Rhizomes take up to three years to reach harvest size of 1 inch diameter; harvest by pulling the whole plant; best flavour comes from grating cleaned roots within 30 minutes of harvest, though roots keep refrigerated for a month. PESTS: aphids, alfalfa looper larvae, crane fly larvae, slugs, snails. DISEASES: leaf spot, root rot, rhizome rot; susceptible to phytophthora blight. Medium maintenance; slow-release 12-12-12 fertiliser adequate for 3-4 months; keep well-watered but not standing in water; prune wilted, damaged or dead leaves to deter pests and disease.
-
Native to East Asia -- Russian Far East (Sakhalin), Japan and Korea -- growing naturally in wet places and by streams in lowland and mountain areas, typically near coasts. Grows in wet soil or shallow water; the highest-quality rhizomes come from SEMI-SHADE IN CLEAR RUNNING SPRING WATER at 11-14°C. Propagate by seed sown in spring in a greenhouse and kept permanently moist, potting seedlings individually for the first year and standing them in shallow water before planting out in late spring or early summer; or by division in spring, with larger sections planted straight out and smaller ones potted until established. Takes 3-5 years to produce marketable roots, though roots of plants 15-24 months old are best for culinary use. The finely grated rhizome is the main edible part, and leaves, flowers and petioles can also be cooked or pickled.
2 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 wasabi in the UK?
In Southern England, from early November. In Scotland, wait until early November. 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 wasabi?
Sow early November to mid December.
What problems affect wasabi?
Our data links 1 disease and 3 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 Wasabis 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 (brassicas & mustards):
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.