How to Grow Leeks in the UK: Complete Growing Guide
Leeks are one of the most rewarding winter vegetables for UK gardeners. Hardy, versatile, and available for harvest from late summer right through to spring, they fill the hungry gap when little else is growing. This guide covers everything you need to grow leeks successfully.
Not sure when to sow? See our When to Plant Leeks UK →
Founder & Head Grower, SoilCommander · RHS Level 2 · 12+ years growing in Yorkshire
I've been growing vegetables on my Yorkshire allotment and raised beds since 2012. Everything I write is based on what I've actually grown, failed at, and eventually got right in a real UK climate.
Watch this short guide to growing leeks at home in the UK — from sowing and transplanting to earthing up and harvesting through winter. Ideal for UK allotment and garden growers.
🌱 Did you know? Leeks are one of the few vegetables you can harvest fresh from the ground right through winter — they actually improve in flavour after a frost.
Quick Growing Facts
- Sowing Time: January to April (indoors from January; outdoors from March)
- Transplant Time: May to July
- Harvest Time: August to April
- Growing Time: 16-20 weeks from sowing to harvest
- Difficulty: Easy to moderate
- Position: Full sun, open site
When to Sow Leeks
- Indoor sowing: January-March in trays or modules for the longest season
- Outdoor seedbed: March-April once soil has warmed above 7°C
- Transplant: May-July when seedlings are pencil-thick (15-20 cm tall)
- Early varieties: Sow January-February for August-November harvest
- Maincrop varieties: Sow February-March for November-April harvest
Soil Preparation
- Soil type: Deep, fertile, well-drained soil
- Add organic matter: Dig in well-rotted manure or compost in autumn
- pH level: Neutral to slightly alkaline (pH 6.5-7.5)
- Firm the soil: Tread and rake to a fine, firm tilth before transplanting
- Avoid waterlogging: Leeks hate sitting in wet soil over winter
How to Sow Leeks
Indoor Sowing (recommended):
- Use trays or modules: Fill with seed compost; sow 2-3 seeds per module or thinly in trays
- Sowing depth: Cover seeds with 1 cm of compost
- Temperature: Keep at 13-16°C; germination takes 14-21 days
- Thin seedlings: Reduce to one per module when large enough to handle
- Grow on: Keep in a cool, bright place until transplanting time
Outdoor Seedbed Sowing:
- Sow thinly in drills 1 cm deep, 15 cm apart from March onwards
- Thin seedlings to 5 cm apart once established
- Transplant when pencil-thick, usually 10-12 weeks after sowing
💡 Top Tip: The Dibber Method
Make 15 cm deep holes with a dibber, 15-23 cm apart. Drop one seedling into each hole and water in — do not backfill with soil. The hole gradually fills as you water, naturally blanching the shank and producing the long white stem leeks are prized for.
Transplanting Leeks
- When to transplant: May-July when seedlings are 15-20 cm tall and pencil-thick
- Trim roots and leaves: Trim roots to 2-3 cm and leaves by one-third to reduce transplant stress
- Make deep holes: Use a dibber to make holes 15 cm deep, 15-23 cm apart, in rows 30 cm apart
- Drop in seedlings: Place one seedling per hole; do not backfill
- Water in: Water each hole thoroughly; soil will gradually fill in naturally
- Firm in: After a few days, gently firm soil around the base of each plant
Ongoing Care
- Watering: Water regularly during dry spells, especially in the first few weeks after transplanting
- Weeding: Keep weed-free; leeks are slow-growing and easily swamped
- Earthing up: Draw soil up around the stems as plants grow to increase the length of blanched white shank
- Feeding: Apply a balanced fertiliser or liquid feed monthly during the growing season
- Frost protection: Maincrop varieties need no protection; early varieties may benefit from fleece in hard frosts
Common Problems
Leek rust: Orange pustules on leaves caused by a fungal disease. Remove affected leaves; improve air circulation. Avoid overhead watering.
Allium leaf miner: White maggots tunnel through leaves and stems. Cover with fine insect mesh from March to April and October to November when the fly is active.
Bolting: Leeks left in the ground too long in spring will run to seed. Harvest all remaining leeks by April.
Thin shanks: Usually caused by late sowing, overcrowding, or poor soil. Sow early, thin properly, and improve soil with organic matter.
Harvesting Leeks
- Early varieties: Harvest from August to November when shanks are 2-3 cm thick
- Maincrop varieties: Harvest from November through to April as needed
- Lift with a fork: Loosen soil with a fork before pulling to avoid breaking the shank
- Harvest as needed: Leeks can stand in the ground until required — no need to harvest all at once
- Before bolting: Harvest all remaining leeks by April before the central stem hardens
Storage
- In the ground: Best storage is leaving leeks in the ground until needed (maincrop varieties)
- Refrigerator: Store harvested leeks unwashed in the fridge for up to 2 weeks
- Freezing: Slice, blanch for 2 minutes, cool, then freeze for up to 6 months
Recommended Varieties
- King Richard: Early, long slender shanks, harvest August-November
- Musselburgh: Classic maincrop, thick shanks, very hardy, harvest November-March
- Bandit: AGM, late maincrop, outstanding frost resistance, harvest December-April
- Oarsman: AGM, mid-season, long clean shanks, good disease resistance
- Megaton: F1 hybrid, very uniform, heavy yields, good for exhibition
Essential Tools & Supplies
Plan Your Vegetable Garden
Get our comprehensive UK Vegetable Garden Planner PDF to plan your entire growing season.
Get the Planner →How To Grow Leeks In The UK
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.
Tools That Help With This Crop
Use these links when the guide moves from reading into sowing, planting, watering, and keeping the crop healthy.
Plan the next step
Use the printable UK Vegetable Garden Planner to turn this guide into sowing dates, bed layouts, and weekly garden tasks.