Growing Leeks

allium porrum : Amaryllidaceae / the onion family

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

(Best months for growing Leeks in USA - Zone 5a regions)

  • S = Plant undercover in seed trays
  • T = Plant out (transplant) seedlings
  • P = Sow seed
  • 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 spring onion (scallion). Grow in seed trays or punnets until about 20 cm (8 in) 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 - 25 cm (8 - 10 in) deep. Set the seedlings 10 - 15 cm (4 - 6 in) 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

13 Jan 08, Liz (Unknown climate)
A tip I read recently but cannot remember the source - use small cardboard tubes, one over each seedling and filled with loose soil, to earth-up the leeks and keep more of the stem white.
18 Sep 08, Michelle (Australia - temperate climate)
Blanching is where you cover the white part of the leek (the base from where the roots start to the first leaves) and you cover it so that it minimises the about of light that gets to it. This procedures will help increase the leek's flavour and nurture the white part of the leek which is beautiful to eat. You can use cardboard toilet rolls, tubing, brown paper bags with elastic bands, or you can simply push the soil up and around the white part of the leek. This 'buries' it so that you only see the green leaves. As leeks can take a few months to grow, this blanching can be done (as a guide only) after about 3 months or so. Hope this helps.
21 Dec 08, Deb (New Zealand - cool/mountain climate)
Why have my leeks all gone hard and woody inside. They are beginning to flower but are still quite thin and woody
16 Jan 09, jacqu (Australia - temperate climate)
i planted some leeks months ago as small plants but they don't seem to be getting any bigger and i don't know why. anyone have any suggestions.
20 Jan 09, willo (Australia - cool/mountain climate)
Hi Jacqu, leeks are "gross" feeders, I.e. Prefer lots of manure, rich soil/compost and water (make sure manure isn't too fresh or plants will burn). I wouldn't worry too much about them, they tend to be slow starters and at least they are still alive!
15 May 09, Barb (Australia - sub-tropical climate)
Something I recently found out about leeks - maybe everyone else already knows this: Instead of harvesting by pulling up the entire plant, you can just cut it off close to the ground (I use strong kitchen scissors) and the leek plant just keeps growing. It ready for its next harvest sooner than waiting for another plant to grow from seed :-)
30 Sep 10, Heather Pearson (New Zealand - temperate climate)
Sounds interesting - will try it. Tried a french lady's tip (from this site) of lifting when 25cms or so, removing third of roots and tops and replanting. Worked a treat and leeks grew so long and fat.
21 May 09, Amanda (Australia - temperate climate)
Have planted my leeks from seedlings. Do I need to separate them into individual plants and replant?
22 May 09, David (Australia - temperate climate)
Amanda. Depends on what size leeks you want. the closer they are the smaller they are. I work on 15cm between plants, gives a nice size.
28 Jun 09, Rhonda (Australia - temperate climate)
I planted some seedlings today. Will I use soil or mulch to put around them as they (hopefully) grow?:
Showing 1 - 10 of 140 comments

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