Growing Leeks

allium porrum : Amaryllidaceae / the onion family

Jan F M A M J J A S O N Dec
S S             S S    
    T T             T T

(Best months for growing Leeks in New Zealand - cool/mountain regions)

  • S = Plant undercover in seed trays
  • T = Plant out (transplant) seedlings
  • Easy to grow. Grow in seed trays, and plant out in 4-6 weeks. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 46°F and 86°F. (Show °C/cm)
  • Space plants: 4 - 8 inches apart
  • Harvest in 15-18 weeks. Loosen with a fork rather than pull by hand..
  • Compatible with (can grow beside): Carrots
  • Almost ready to use
  • Leek

A member of the onion family. Looks rather like a large scallion or spring onion Grow in seed trays or punnets until about 20cm (8in) tall. They look rather like large blades of grass at that stage. Then plant out into trenches or individual deep holes. The aim is to blanch the stems while the plants are growing. Trenches should be about 20-25cm (8-10in) deep. Set the seedlings 10-15 cm (4 - 6in) apart then add enough soil to just cover the roots. As the plants grow fill the trench. Otherwise - make holes with a dibble or suitable stick 15 cm (6 in) deep and 3-4 cm (1.5 - 2 in) wide. Drop a seedling in each and water enough to cover the roots with soil. As they grow, watering will gradually fill the hole.

Leeks prefer moist clay soils. Keep soil moist and loose, mulch will help.

Culinary hints - cooking and eating Leeks

Trim off the roots and any damaged leaves.
Young ones can be used whole with some of the green leaves
Wash thoroughly as the earth tends to get inside.
Chop and fry in butter (or olive oil) until tender.
Can be added to casserole meals, allowing time to cook through.
Leek and mushroom make a tasty combination for a tart filling.

Your comments and tips

07 Apr 22, Murray Patterson (New Zealand - temperate climate)
Hi Annette, It appears that you may have Cutworm problems. I have had these in my garden and they cut the small plant at the base. I have now got around this by planting my small plants in toilet rolls which I place in the ground and have about 5 cm above ground. Around this I have cut a hole in some tinfoil paper and placed it over the toilet roll so it has what you could call a skirt over the ground and this has cured my cutworm problem. They do not seem to like it at all. As they come out at night to eat I think the foil has deterred them. Murray
19 Mar 22, Dionne (Australia - sub-tropical climate)
We grown American Flag with great success. We mostly direct seed and sometimes transplant. We always broadfork a bed before planting and add a little ag lime (especially pre-seeding with alliums). We don't let them get gigantic like you see in the shop. You can, but that requires transplanting into a small trench and then hilling up to blanche. We find the bunches of baby leeks just as popular as the large ones. Leeks with asparagus are so wonderful on pizza with a good French sorrel and parsley pesto base! Leeks can handle more water than you realise.
06 Dec 20, Terry Shannon (Australia - temperate climate)
My Welsh Wonder leeks are always skinny looking occasional .two-finger thickness is the best we ever get. I fertilize them and they get plenty of water and are in sandy neutral soil We look at the produce in the stores and despair :-( I shall appreciate any suggestions Cheerio.. terry
07 Dec 20, Anonymous (Australia - temperate climate)
I would suggest an autumn planting. Maybe build your soil up with compost and manures 2-3 mths before planting. Make sure it is all rotted into the soil by plant time. Hard to beat the commercial people, they are spot on with fertiliser requirements and watering. We kind of half guess it.
19 Nov 20, Sheryl Gordon (USA - Zone 9b climate)
Can I direct seed outdoors in flats in November after it cools down? I don’t have space indoors to start seeds.
23 Nov 20, Anonymous (USA - Zone 9b climate)
Read the planting guide for growing leeks in your zone. It is the monthly calendar at the top of the page.
24 Sep 20, Tshidiso (South Africa - Dry summer sub-tropical climate)
What are part consumes of leak regarding flower,Leaf and bulb??
27 Sep 20, (South Africa - Semi-arid climate)
Read the notes here, down the bottom of the page.
15 Jun 20, Delene Bezuidenhout (South Africa - Summer rainfall climate)
Where can I buy leek plants? When is the best time to plant them in Johannesburg?
16 Jun 20, Anon (South Africa - Humid sub-tropical climate)
You plant by seed. Work out your Climate Zone from the BLUE TAB at the top of the page. Then see when you plant for that climate zone. The monthly calendar at the top page tells you when to plant.
Showing 1 - 10 of 131 comments

I always plant seeds on Nov 1st in a nursery bed ,use liquid feed to raise . Febuary I plant by the moon Calendar When planting I dib hole 150 mm deep ,place in two sheep pellets and water in . Trim tops and root before planting .If too hot cover in shade cloth, and water regulary until established. Have had good sucess in the past.

- lez Howard

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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. GardenGrow is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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