How to Grow Leeks in the UK – Planting, Care and Harvest Guide

Leeks occupy a unique place in the UK kitchen garden – they’re one of the very few vegetables that can be harvested fresh throughout the winter months, filling the hungry gap when almost nothing else is producing. Planted out in summer and left to develop through autumn, they stand through frost and snow and can be pulled as needed right through to March. For a winter-active kitchen they’re invaluable.

Best leek varieties for UK gardens

Sowing and raising transplants

Leeks need a long growing season – sow indoors from February to April for planting out in June and July.

1. 1
   Sow thinly in modules or a seed traySow 2-3 seeds per module or thinly in rows across a seed tray. Cover with 1cm of compost and keep at 15-18°C for germination – a warm windowsill works well.
2. 2
   Thin to one per moduleOnce seedlings are a few centimetres tall, remove the weaker ones leaving one per module. Don’t worry if they look thin and grass-like – leek seedlings always do at this stage.
3. 3
   Grow on until pencil-thickLeeks are ready to plant out when approximately pencil thickness – typically 20-30cm tall. This takes around 12 weeks from sowing.

Planting out – the dibber method

The traditional method for planting leeks produces the longest white shanks and best yields:

1. 1
   Make holes 15cm deep with a dibberPush a dibber or thick cane 15cm into the soil at each planting position. Space holes 15cm apart in rows 30cm apart.
2. 2
   Drop one leek transplant into each holeTrim roots to 2-3cm and leaves to about half their length before dropping into the hole. The leek should sit with just the tip of the leaves showing above the hole.
3. 3
   Water into the hole – don’t fill with soilWater each hole thoroughly. The water settles enough soil around the roots to anchor the plant. As the leek grows the hole gradually fills naturally – this blanches the shank white.

Care through the season

• Water in dry spells – leeks need consistent moisture, particularly in July and August while establishing
• Weed regularly – leeks grow slowly and are easily outcompeted by weeds
• Earth up in autumn – mound soil around the shanks in October to extend the blanched white portion
• No need to feed heavily – a balanced general fertiliser in midsummer is sufficient

Harvesting

Leeks are harvested as needed from October through to March. Loosen with a fork before pulling – they develop extensive root systems and pulling without loosening often snaps the shank. They’re finest when harvested young and tender at 2-3cm diameter rather than left to become large and coarse.

Common problems

Leeks are one of the most satisfying winter crops in a UK kitchen garden – standing through frost and snow and providing fresh harvests when almost nothing else is available. For more on planning a productive raised bed through the colder months read our UK seasonal planting guide.