How to Grow Leeks

Leeks are a fantastic green and nutritious vegetable to grow for harvests in the winter, when there’s not a huge amount growing in the garden and harvests aren’t at their greatest. 

When to sow leeks:

When you sow leeks is dependent on when you would like them ready to harvest:

  • Winter harvest: Sow seeds directly in the ground from Mid-March to mid-April.
  • Spring harvest: Sow seeds in June for spring harvests the following year.
  • Autumn harvest: Sow seeds in early March, as the weather varies in March year to year.

You can also sow under glass in late winter for transplanting in mid-April for an autumn to early winter harvest.

How to sow leeks:

Sow thinly in drills (shallow furrows made with the edge of a hoe) outdoors and thin out gradually until the remaining seedlings are about 5cm apart. If sowing under glass, add two to three seeds to a small pot, and remove the two weaker seedlings once the seedling show around four leaves.

When do leeks germinate?

Leeks typically take between 2-2 ½ weeks to germinate, you’ll notice the leek stems start to appear through the top of the soil.

How to plant leeks?

Young plants should be transplanted into the ground in June. They should be about 20cm in length and about the thickness of a pencil. For their eventual planting hole use a dibber to create a long thin hole 15cm deep.

Drop the young plants in the holes and fill the holes with water. You don’t need to fill the soil with soil as the leeks will swell to fill them.

For plants already grown we recommend you unpack and examine them upon receipt. If they have dried out during transit they will benefit from a gentle watering:

  • Plant out as soon as possible when conditions allow in a sunny spot where available.
  • Prepare the soil well before planting, incorporate a good quality compost and water well.
  • Prepare holes 4-6in (10-15cm) deep with a dibber and set the plants gently with out firming them in.
  • Fill the hole with water, this will consolidate the plants sufficiently.
  • Ensure the soil bed is well watered throughout the season and weed well.

How to feed leeks:

It pays to prepare the soil well before sowing leeks or adding young plants:

  • In the winter add lots of bulky compost or manure to the soil to increase the nutrient levels.
  • To top up and really put the young plants in good stead, add a general purpose fertiliser a couple of weeks before sowing or planting.
  • To increase the thickness of stems feed regularly until mid-summer. 
  • If you prefer leek-whites to leek-greens earth soil up gently while they are growing, making sure you don’t get soil in between the leaves.

How to water leeks:

Water seed beds after sowing or containers if growing early crops indoors. When transplanting leeks into their final hole, fill the hole with water as this settles and firms the roots, while they thicken to fill the hole. 

Water leeks during dry weather. They are quite self-sufficient when they are not competing for water with surrounding weeds – so keep these to a minimum – or not exposed to long periods of dry weather.

What temperature to grow leeks in:

Leeks appreciate a sunny spot so bear this in mind when sowing or planting.

How to harvest and store leeks:

For early harvests from seeds sown indoors in winter, harvest in autumn lifting leeks from the soil gently. For seeds sown in the main season of spring, harvest throughout winter, and for those summer sowings, you can expect to lift leeks in spring the following year. 

Leeks will store for up to a week in the fridge. By sowing over a period though through the spring you can have crops all though winter and into spring the following year.

Best Varieties of Leek:

We recommend the following leek varieties:

Krypton: An early compact leek ready from as early as August and holding well in the ground until March the following year.

Musselburgh: An old established favourite with short, thick stems and a mild flavour.

Pests and Diseases of Leeks 

Generally trouble-free other than leek moth.