How to Grow Leeks UK
On this page
- Leek (Allium ampeloprasum var. porrum)
- Watch: Growing Leeks at Home
- Regional Planting Calendar
- Quick Facts
- At a Glance
- Soil & Growing Conditions
- Growth Stages
- Harvest & Storage
- Diseases
- Pests
- Companion Planting
- Leeks, Seed to Harvest
- Plan your Leeks planting
- Growing Leek in another region
- References
- Frequently Asked Questions
- Leeks in brief: the short answer
In the UK, leeks are sown mid February to mid June, and planted out early May to mid July.
Timing is the decision that matters most in the UK: there are 4 separate regional planting out windows, ranging from early May in Southern England to early June in Scotland.
The short answer
- Sow
- Mid February to mid June
- Plant out
- Early May to mid July
- Site
- 6+ hours of sun, soil pH 6–6.5
- Biggest risk
- Allium white rot
Core growing advice on this page is checked against named horticultural sources — see References.
Leek (Allium ampeloprasum var. porrum)
14 sources cited · Verified
Watch: Growing Leeks at Home
A quick SoilCommander video on growing leeks at home in the UK — from sowing and transplanting to earthing up for a long white shank.
Regional Planting Calendar
| Region | Sow | Plant out |
|---|---|---|
| Southern England | mid February to mid June | early May to mid July |
| Midlands derived | early March to mid June | mid May to mid July |
| Northern England derived | mid March to late June | late May to late July |
| Scotland derived | early April to late June | early June to late July |
Rows marked derived are interpolated between regions our sources do state, because no source we consulted gives a figure for that region specifically. They are deliberately wider to reflect that uncertainty.
Southern England - detail & sources
Sow leek seed indoors from late winter (keep above 10°C) or outdoors from March; transplant pencil-thick plants from about May, and start pulling from late summer with hardy late cultivars standing through winter into spring. Southern England has the UK's earliest soil-warming and last frosts (Met Office), so the earliest sowing and transplanting apply here.
Midlands - detail & sources
DERIVED: sowing and transplanting run roughly two weeks later than southern England because the Midlands warm and pass the last frost later (Met Office south-to-north gradient). Leeks still stand through the winter for a long harvest.
Northern England - detail & sources
DERIVED: about four weeks later than southern England for the earliest sowing and transplanting, reflecting the Met Office south-to-north warming gradient. Hardy leeks overwinter well even in the north.
Scotland - detail & sources
DERIVED: the latest UK start - sow from about April and transplant from early June, as Scotland is slowest to warm (Met Office). Very hardy leeks are well suited to Scottish winters and give a valuable late crop.
Quick Facts
| Factor | Value |
|---|---|
| Soil pH | 6 - 6.5 |
| Sunlight | 6-10 hours direct sun |
| Germination temp | 10°C |
| Optimal growing temp | 18-24°C |
| Minimum survivable temp | -5°C |
| Soil texture | RHS: improve soil by "digging in two bucketfuls of garden compost or well-rotted manure per square metre/yard". |
| Drainage | RHS: "Choose a sunny spot with free-draining soil". |
| Lifecycle | Hardy biennial grown as an annual: the blanched shank is harvested in the first season and stands through winter frosts. Plants flower and set seed only in a second year after cold; the crop is very frost-hardy and is not lifted for storage but left in the ground until needed. |
| Edible parts | stems (white base/shank), flower buds (scapes) |
At a Glance
Soil & Growing Conditions
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Sowing & Germination | 0 | Leeks are grown from seed. SOWING DEPTH: sow seed 1.5cm (about half to three-quarter inch) deep - indoors in modules or trays in late winter (keep above 10°C/50°F), or outdoors from March to April in a shallow drill, watering the base first and sowing thinly, with rows about 30cm (12in) apart. Later sowings in May-June give leeks for winter and spring. Grow the seedlings on until they are about 20cm (8in) tall and pencil-thick, ready to transplant (roughly eight weeks from an indoor sowing). |
| Transplanting & Establishment | 3 | This is the step that gives leeks their long white shank. When seedlings are pencil-thick, lift them and trim the roots to about 2.5cm (1in). PLANTING DEPTH & SPACING: with a dibber, make holes about 15cm (6in) deep and 5cm (2in) across, spacing them 15-20cm (6-8in) apart in rows 30cm (12in) apart. Drop one leek into each hole and "puddle in" by filling the hole with water - do NOT backfill with soil; the loose hole blanches the lower stem white as it grows. Water the young plants until they are established, then keep the bed weed-free so the shallow-rooted leeks are not crowded. |
| Shank Development & Blanching | 7 | Over the following months the shank thickens and lengthens. To lengthen the white (blanched) portion, draw dry soil up around the stems several times through the season (earthing up), taking care not to let soil fall into the centre of the plant. Water only during prolonged dry spells once established - leeks are shallow-rooted and drought reduces yield - and keep weeding. Watch for orange leek rust on the leaves and cover with insect-proof mesh where allium leaf miner or leek moth are a problem. |
| Harvest | 8 | Leeks can be harvested at any size: pull baby leeks from late summer, or leave plants to reach full size. They do not need lifting for storage - being very frost-hardy, they stand in the ground and are lifted fresh as needed, with hardy late cultivars cropping right through winter and into spring. Gently lift each plant with a fork rather than pulling, to avoid snapping the shank. Days from sowing to first harvest range from about 60 (baby leeks) to 180 or more for full-sized winter leeks. |
Harvest & Storage
Diseases
Pests
Companion Planting
Leeks, Seed to Harvest
Plan your Leeks planting
When to sow and plant Leeks depends on your own frost dates. Check the UK vegetable planting calendar, or the month-by-month guides that cover Leeks: January, February, March, May, June, July, October, November, December. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Leek in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
References
-
Qualitative only: southern/coastal last air frost often before end of April; further north well into May, in a few places into June. No numeric per-region frost dates published here.
-
US extension source: leek is a hardy cool-season biennial; transplants need 6-8 weeks of growth before planting out; sow 1/4-1/2 in deep and thin to 4-6 in apart in rows 8-16 in apart; harvestable as early as 60 days after seeding but generally 100-120 days to mature; hilling blanches a longer edible stem; water to 18 in depth every 7 days; side dress 1/4 lb 21-0-0 per 100 sq ft in mid-May and again late June; harvest at 1 in stalk diameter; store at 32-40°F in humid conditions such as wet sand.
14 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 plant leeks out in the UK?
In Southern England, from early May. In Scotland, wait until early June. Treat these as a guide rather than a fixed date — the governing rule is to plant out only once frost risk has passed and temperatures are reliably warm enough.
When do I sow leeks?
Sow mid February to late June, at around 10°C for germination.
What soil pH do leeks 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 leeks?
Our data links 4 diseases 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.
Last verified 2026-08-06
Leeks in brief: the short answer
To grow leeks in the UK, sow seeds in late winter or spring, grow seedlings on until they are sturdy, then transplant them into prepared soil with enough space to thicken. Keep leeks watered in dry weather, weed around young plants, and harvest from late summer through winter depending on the variety and sowing time.
For detailed month-by-month timing, see when to plant leeks in the UK. Use the UK Vegetable Garden Planner PDF to track sowing dates, transplanting dates, bed positions, and harvest notes.
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.