How to grow leeks

Discover how to grow leeks for a steady supply of flavoursome veg you can enjoy all winter long

how to grow leeks
(Image credit: Getty Images)

Learning how to grow leeks is a must if you want a supply of fresh veg all winter long. As leeks taste milder and sweeter than onions, they're perfect in all kinds of dishes, from casseroles to risottos. Traditionally, it's just the white part of the leek that's eaten but the tougher green leaves are perfect for adding to soups and stocks.

Leeks do need quite a bit of space to grow, so are best planted in beds, but you could grow a few in raised beds or deep containers if your garden is on the smaller side. They're normally grown away from your main veg patch to start with and then moved over later in the summer once your fast-growing crops, like lettuce, have gone.

Here's our simple guide to growing leeks, including how long it'll take, and how to avoid common problems. To find out how to grow other winter fruit and veg, head to our grow your own hub for more great advice

Where to buy leek seeds online

Step-by-step guide to growing leeks

1. Leek seeds should be sown in pots from February to April, then planted out between May and July.

2. Fill small pots with compost, scatter with seeds and cover in about 0.5cm of compost. Keep the moist until your seeds germinate and then thin out.

3. Once your seedlings are established (or if you decide to grow from seedlings rather than seeds), pull the roots apart and move to larger pot with compost between.

4. When you're ready to plant out, dig out your soil and remove any big stones. Dig through some well-rotted manure or compost.

5. Leeks are ready to go into the ground when they're at least 15cm tall. Make holes in the soil about 15cm deep and 15cm apart. A broom handle can be useful for this. Make sure your rows are 30cm apart. 

6. Lower a leek plant into each of the holes.

7. Water well and cover with pegged-down horticultural fleece to protect.

8. To increase the length of edible white stem, you can gradually draw dry soil up around the stem in stages. Try not to get soil between the leaves.

how to grow leeks

(Image credit: Getty Images)

When are leeks ready to harvest?

Leeks are a winter veg, so will be ready to harvest from August to December, depending on the variety you choose. You can leave them in the ground throughout the winter months and pick as and when needed. Always lift your leeks from the ground gently using a garden fork.

TOP TOP: If you start lifting your leeks when they're quite small, it will help lengthen your harvest period. 

What are the best varieties of leek to grow in the UK?

According to the RHS, some of the best varieties of leek to plant in your garden are:

  • Carlton AGM – a quick-growing variety you can harvest from September to November
  • Pancho AGM –  has long, crisp white stems, so plenty to eat!
  • Apollo AGM – ready to harvest in December with good rust resistance

Common problems when growing leeks

The biggest threat to your leeks is leek rust, a fungal disease that causes yellow spots on the leaves. Most mild cases won't affect your crop, but more serious infections can cause leaves to shrivel up. 

To prevent leek rust, space your plants out well to reduce humidity around the roots. If you do get leek rust, you'll need to get rid of any badly infected plants and then you can't grow onions, leeks or garlic in the same location for the next three years.

You should also make sure you cover your leeks with horticultural fleece when you first plant them out to protect from leek moth. 

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