How to Grow Leeks From Seed (A Simple Guide for UK Gardeners)

Leeks are one of my favourite crops to grow. They’re reliable, hardy, brilliant value for money, and they slot perfectly into the veg garden from autumn right through winter. And the best bit? They’re incredibly easy to grow from seed.

When to Sow Leek Seeds

In the UK, the ideal sowing window is:

• Late February to April for early and maincrop leeks
• May to early June for later varieties

Sow earlier for big winter leeks, later for slimmer summer ones.

What You’ll Need

• Leek seeds
• Seed trays or deep modules
• Fine seed compost
• A watering can with a fine rose
• Labels (trust me, you’ll forget which variety is which)

How to Sow Leeks From Seed

1. Fill your trays with seed compost

Leeks like a fine, free‑draining mix. Gently firm the compost but don’t compact it too much.

2. Sow thinly

You can sow in two ways:

Option A: In trays

Scatter the seed thinly across the surface, then cover with a light sprinkle of compost.

Option B: In modules

Drop 4–6 seeds into each module. They’ll grow together in a little clump, which makes transplanting very easy.

3. Water gently

Use a fine rose so you don’t blast the seeds out of place.

Keep the compost moist but never soggy.

4. Give them some warmth to germinate

A windowsill, greenhouse or propagator is perfect.

They don’t need high heat — just a bit of protection from cold nights.

5. Grow them on

Once the seedlings are up, they’re happy in cooler conditions.

Good light is more important than warmth at this stage.

Planting Out Your Leeks

You’ll know they’re ready when they’re about pencil‑thick — usually late April to June.

How to plant them:

1. Use a dibber (or the handle of a trowel) to make holes about 15cm deep.
2. Drop one seedling (or one clump) into each hole.
3. Don’t fill the hole with soil. Just water it in and let the rain gradually fill the hole over time. This is what gives you that lovely long white stem.

Spacing:

• 15cm between plants
• 30cm between rows

Caring for Your Leeks

• Keep them weed‑free
• Water during dry spells
• Mulch around the base to help blanch the stems
• Earth them up slightly if you want longer white shanks

They’re very low‑maintenance — one of the reasons I love themHarvesting

Depending on the variety, you can harvest from August right through to March.

To harvest, simply twist and lift. If the soil is heavy, use a fork to loosen it first.

What to Do With Them

Leeks are incredibly versatile:

• Soups
• Pies
• Stir‑fries
• Roasts
• Pasta dishes
• Or simply sautéed in butter

And of course, they’re the star of this week’s supporters‑club recipe.

Final Thoughts

If you’re new to growing veg from seed, leeks are a brilliant place to start.

They’re forgiving, productive, and they fill that hungry gap when not much else is ready.

If you’re sowing along with me this month, let me know how yours get on — I love seeing your progress.