Growing Leeks From Sowing to Harvest

, written by Benedict Vanheems gb flag

Rows of large leeks

You’ve got to admire leeks. They’re exceptionally hardy, generally trouble-free, and best of all they will provide beautiful long stems from autumn right the way through to spring at a time when other harvests are thin on the ground. Now’s the time to start thinking about sowing them…so let’s get started!

Luscious Leeks

Leeks are very hardy vegetables, which in most regions will safely sit through frost and snow to be lifted as needed. You can prolong the harvest period by selecting a mix of varieties. Early season leeks are less hardy but will be ready for autumn, while mid and late season leeks will give you smooth stems for winter and spring.

Grow leeks in a sunny, open position in well-dug soil that’s had plenty of organic matter added to it. The fungal disease rust can be a minor problem from summer onwards, so look out for varieties described as ‘rust resistant’ and make sure you leave enough space between plants for good air movement.

Sowing Leeks

The earliest varieties can be sown under cover from late winter, with others following on from mid spring. Leeks are usually sown in pots or trays of compost and then transplanted into their final position when they’re big enough.

Leek seedlings in tubes

For guidance on when to start sowing why not try our Garden Planner, which uses data from your nearest weather station to recommend the best times to sow, plant and harvest your crops.

Sowing is very easy. Start by sieving potting compost into pots or trays. Gently tamp the potting compost down then sow the seeds very thinly so they fall about an inch (2-3cm) apart. You can also sow two seeds per cell in a module tray. Now cover them over with a thin layer of more potting compost, and water them. Keep the potting compost moist as the seeds germinate and the seedlings grow on.

Early sowings should be placed on a sunny indoor windowsill or into a greenhouse where the warmth will encourage quicker growth. As the seedlings grow you can if you wish separate them out and pot them on into individual pots.

Transplanting Leeks

Before transplanting your young leeks make sure you’ve acclimatised them to outdoor conditions by leaving them outside for increasingly longer periods over the course of one to two weeks. They’re ready to transplant when they are six to eight inches (15-20cm) tall.

Planting out leek seedlings

Begin by ‘dibbing’ (poking) holes that are about the same height as the leek seedlings' stems into well-dug soil. You can use a purpose-made dibber for this, or improvise with a cut-down handle from an old broken spade or fork, or even use the handle-end of a hand tool such as a trowel. Make one hole for each plant. The holes should be about six inches (15cm) apart, with a foot (30cm) left between rows, or if you’re planting in blocks space then seven inches (20cm) apart each way.

Now carefully remove the leeks from their pots and, if they haven’t already been potted on, tease the roots apart. Place the seedlings into the holes. It’s important that the roots reach right down to the bottom of the hole, so if necessary, help them along – you may need to trim them to get them in if they’re very long.

With your leeks in position, fill the holes to the brim with water and leave to drain. Do not fill in the holes. The soil will naturally fall back in with time, allowing the shanks (stems) to swell easily.

Puddling in leeks

Caring for Leeks

If you want to maximise space you can grow fast-growing salad leaves in between your newly planted leeks while you wait for them to establish. Salad crops are shallow-rooted so they won't compete with the deeply-planted leeks. By midsummer the leeks will need all available space to encourage high light levels and good air circulation.

Easy-care leeks need very little attention. Water the plants in very dry weather and keep the ground between the leeks weed-free by hand weeding or hoeing weekly.

If you want really long, white stems, you can ‘blanch’ your leeks two to three weeks before you want to harvest them. Simply draw the soil up around the shanks to exclude light, or tie cardboard tubes around the stems.

Harvesting Leeks

Leeks can be harvested as soon as they’ve reached the desired size. Slip a fork underneath the plant to lever it out, while pulling up on the leaves. Trim the roots and any damaged leaves onto the compost heap then wash away the soil ready for the kitchen. Hardy varieties may be dug up as needed over the winter, though in very cold areas you may want to dig them up before the ground freezes solid.

Cheesy, creamy leeks

Leeks are very versatile vegetables, and can be added to all manner of recipes, including stir-fries, quiches, soups, pies and tarts. For a luxury side dish try adding cream and grated cheese to sautéed leeks before serving piping hot with a grind of the pepper and salt mills. Mmm!

Look after your leeks and they’ll love you back! If you’re already in the know about leeks and fancy sharing some cultivation or culinary tips, do drop us a comment below. Happy sowing!

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Show Comments


"When I grow leeks they always develop a main stem and go to seed/flower. What causes this?"
Dave Ellison on Friday 6 October 2017
"Leeks usually go to seed (or bolt) in response to a spell of cold weather. To avoid this, make sure you sow them at the right time so they aren't exposed to really cold weather early on in their life. Leeks grown to harvest over winter will usually go to flower as soon as the weather warms up in spring. Sometimes excess fertiliser can lead to bolting, so only nourish your leek beds with organic matter, applied the season before planting. Also, transplanting the leeks while they are still quite thin and small will reduce the risk of bolting."
Ben Vanheems on Friday 6 October 2017
"do you cut off the scapes ? or do you leave them?"
lee on Wednesday 18 July 2018
"do you cut off the scales? it's july and i planted starts in april. the plants are healthy and about 3-4' high. our weather is hot for a few days then cool for a few days. in a double row i have just 4 plants that have flowering stems/scapes. with my garlic i cut them off, should i do the same with leek scapes. the leek scape is quite thick, thumb thickness."
lee on Wednesday 18 July 2018
"Hi Lee. Yes, cut off the leek scapes/flowers to concentrate the plants' energy into the stem."
Ben Vanheems on Friday 20 July 2018
"I sowed leek seeds 2 years ago, then planted them out in May. Things happened and the garden was neglected. I'm back now and find young leeks in the exact drills that I planted them in 2 years ago. Will they grow as a normal crop? Or will they run to seed? "
Catherine Scott on Wednesday 27 February 2019
"If they are young leeks then it suggests the original leeks produced flowers and set seed, which then fell to the ground to produce the seedlings you see. So there's every chance they will in fact grow into useable leeks - an unexpected bonus!"
Ben Vanheems on Thursday 28 February 2019
"Is it recommended to trim the roots when transplanting young seedlings?"
Alan Sayner on Saturday 27 April 2019
"Traditionally this was done, but it makes no sense because the roots are the lifeblood of the plant. Instead, leave the roots untrimmed and concentrate on gently feeding the roots so that they go right down into their allotted hole. "
Ben Vanheems on Saturday 27 April 2019
"When I plant my leeks I like to how a deep 8-10" trench and keep pulling the soil in as they grow. Very long stems"
Kurt CurtisDP on Tuesday 11 February 2020
"Great tip, thanks for that Kurt."
Ben Vanheems on Tuesday 11 February 2020
"I am experimenting with inter-planting vegetables in my flowerbeds, as I need to reduce the size of my vegetable garden. I will be trying to grow leeks for the first time this year in Kansas, USA. The plants in your first picture are gorgeous with their arched leaves. Is this a product of horticulture methods or the variety planted? If variety, can you give me the name(s) of ones that have leaves like those pictured? Or can you give me pointers on conditions/plant care that keep the tops of the plants attractive until harvesting? Thank you so much! "
Ruth Frank on Wednesday 12 February 2020
"Hi Ruth. Leeks can look very attractive in their own right. The leeks in the picture at the top were taken at one of the Royal Horticultural Society's flower shows, so would have been of exceptional quality and decorative value! I'm not sure which variety it would have been though. But generally if you opt for an F1 hybrid the leeks tend to come out 'neater' and more uniform, which may help with the desired visual effect. Enjoy growing them - they're great veggies!"
Ben Vanheems on Monday 17 February 2020
"started leeks inside the house. They grew to about 6" and they are just single stem. when do I put them outside. They seem healthy. "
Ed. on Saturday 23 May 2020
"Hi Ed. I would put them outside from now. They generally say to plant them once they reach pencil thickness, but they can be quite a bit thinner than this and about 6-8 inches tall would be about right. If there's space in the pot still though, you could move them outside and grow them on for another week or two to thicken up a little more before planting."
Ben Vanheems on Monday 25 May 2020
"Do you trim the top of 5he leeks when planting out"
Mr Roger Curtis on Wednesday 27 May 2020
"Personally, no. But I know some gardeners do do this. But not me."
Ben Vanheems on Wednesday 27 May 2020
"I planted leek seeds directly in my garden, now they are 5-7 inches long. When and at what size should I thin them out? Thanks"
omar nuri on Sunday 14 June 2020
"You can thin them out in stages until they are at their final spacings. This gives a bit of peace of mind in case a few leeks die in-between each thinning - and the thinnings will provide young plants that can be used in salads or lightly steamed or stir-fried, much like salad/spring onions. I would start thinning them out from now, and then again in another few weeks - so long as the plants have enough room to continue growing unhindered - until you reach the final spacing."
Ben Vanheems on Monday 15 June 2020
"I have leek plants in pots in my greenhouse now [oct] about 4 inches high , can I plant them outside now or wait ?"
andy on Wednesday 21 October 2020
"Hi Andy. It's very, very late to be planting leeks, so I fear you may have missed the boat. That said, there's nothing to be lost from planting them outside now - as soon as possible. There's still a bit of growth left to be done before winter stops play. And they may well grow away nicely in early spring to give a useable crop in April/May. At the very least you'll be able to enjoy them as baby leeks - lightly steamed or even served like spring/salad onions."
Ben Vanheems on Thursday 22 October 2020
"Where did you get the mini green house at 1:55 in the video for growing leeks? "
Carol Nies on Saturday 7 November 2020
"There are many variants of this greenhouse. Search 'wooden growhouse' on Amazon and you'll find models the same or very similar to the one in the video."
Ben Vanheems on Monday 9 November 2020
"Is it still safe to leave leeks in the ground in mid-April in the year after they were originally planted, or are they past the harvesting stage by then? If they have now reached the point where they should already have been harvested, what's the best way to store them so they keep fresh when out of the ground? "
Jonathan Wilkinson on Saturday 10 April 2021
"Hi Jonathan. You can leave leeks in the ground as long as you dare! Basically they'll be fine if they're behaving themselves - looking like 'normal' leeks. But very soon they will start to elongate and initiate flower production. The plants will very obviously stretch/thin and then the flower bud will form. At this point the stems go harder and the leeks will be inedible. I would say you have one or two weeks left at the most, though some varieties continue into May. This late in the season, you're best lifting them when they're at their end, and then simply storing them in the fridge, where they will keep for at least a week and up to two."
Ben Vanheems on Tuesday 13 April 2021
"You've given me the courage to try growing leeks. Thanks for the excellent information! "
Dianna on Wednesday 2 June 2021
"I planted leeks from seed in late spring in a raised garden. They germinated and grew to ~3" and stopped in their tracks for the rest of the season. Any advice on how I can improve things for next spring?"
Mark Pasternack on Sunday 21 November 2021
"Hi Mark. There's no specific advice other than to make sure you're giving your leeks everything they need: enough space between plants, a spot with plenty of sunshine to help with growth, and plenty of soil moisture too, so they aren't struggling. The soil needs to be fertile, so it may be worth improving the ground with plenty of well-rotted compost in the weeks before planting, so the roots have plenty to tap into as they grow - to give them the resources they need to thrive."
Ben Vanheems on Tuesday 23 November 2021

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