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Allium porrum

11th October 2020 – this is the sixth year of growing cabbage and leeks in two no-rotation beds in the centre

Leeks are ‘a bundle of leaf sheaths’. Wikipedia gives this definition and I like it. Leeks are not stems or stalks, and a one-word term often used is ‘shank’.

Leeks are closely related to onion and garlic, but have a milder and sweeter flavour.

  • Winter leeks with shorter stems, mostly below soil level, are hardy to deep frost and give fine harvests in early to mid-spring.
  • Summer and autumn leeks have most shank above ground and risk rotting after temperatures below about -6° C/21 °F.

Harvest period

  • Days from seed to first harvest: 150, and up to 380 for the last harvest from a sowing of winter leeks.

One sowing of, say, an early variety and a late variety, can give several transplanting opportunities at different times. Then you have a range of harvest dates over several months.

  • Best climate broadly ranges from continental to temperate. Plenty of moisture is the main requirement for strong growth.

Why grow them

Leeks offer a long season of harvest and are a kitchen staple from autumn to early spring. You can use them like onions, but the flavour is more creamy and sometimes even sweeter.

  • For winter harvests, leeks are especially suitable for temperate climates. They are in the garden for harvesting at any point, over several months.

Leeks are an excellent hungry gap harvest. Grow some winter varieties and leave them to grow through early spring. Some of my most valued harvests here are in the last two weeks of April, from sowings of more than a year earlier. They have doubled in size during the previous month as it warms up, and until they switch to flowering mode.

The transplant stage in July – these three-month-old leek plants are ready to go in, after a potato harvest
An abundant harvest on an icy January morning – the Philomene leeks were harvested after frosts of -5° C/23° F on 2nd January
Two varieties for winter – the middle one is an autumn variety that survived winter but is starting to flower; this is 2nd May – from left: Musselburgh, Autumn Giant, Apollo

Pattern of growth

Most varieties of leek grow slowly and surely through a whole year, for as long a time as almost any vegetable.

  • Sow in mid-spring. Earlier sowing is possible, for summer harvests, but keep frost off seedlings to reduce the risk of bolting.
  • You can propagate seedlings, which become medium-sized plants, over a period of two to three months.
  • Meanwhile, an early vegetable is coming to harvest, such as spinach, lettuce, cabbage, carrots and potatoes.
  • Then transplant at any point in summer.
  • Growth is rapid through autumn and continues slowly in mild winters.
  • In winters below about -8° C/18° F, even leek shanks of winter varieties will benefit from some protection, such as by earthing up. Or harvest before prolonged freezing.
  • Flowering is in mid-spring, according to the variety. A flower stem develops at that time (see the photo above) and is edible when young, similar to the scape of garlic.

Suitable for containers/shade?

Leeks grow really well in containers, partly because they do not need much space for leaf growth. That huge number of leeks you see in the photo below, from the one pot, did not fill any huge volume of space around the pot.

Contrast this with, say, potatoes, which need a large surface area to grow their leaves and stems compared to the container’s size.

Shade is possible for leeks, with some decrease in growth. However, do not grow them where tree roots are sucking soil moisture – in that situation, containers work better. Water containers thoroughly, every day once leeks are large.

The leeks I grew here had no feeding, then, after harvest, I emptied the pot contents onto a bed. The compost had fewer nutrients, but was still valuable organic matter.

Container-grown King Richard leeks on 18th October – the pot was filled with multipurpose compost and regularly watered


Early varieties, sometimes called summer leeks, are King Richard, Jolant and Bulgarian Giant. They all grow long shanks above ground and can yield a lot of food. Then, as autumn turns cooler, they lose some outer sheaths to decay and risk damage when nights fall below about -4°C/25° F.

With Bulgarian Giant leeks, at Lower Farm in October
Untidied Hannibal in November – a multisown autumn variety that may stand through winter if it’s not too frosty
Harvesting Toledo leeks in January – a winter variety that has withstood temperatures of -12°C/10 °F

Autumn varieties are epitomised by the Autumn Mammoth types. They grow faster than winter leeks, with more shank above ground. Varieties include Autumn Mammoth 2, Hannibal, Haldor and Tornado. Plus there are hybrids such as Oarsman F1.

Mid-October – these Philomene multisown leeks were transplanted after potatoes, 13 weeks earlier

Winter leeks have a darker green leaf on a shorter shank, and the original Musselburgh (a village near Edinburgh, Scotland) is still available. I find it almost too short, hence low yielding, and I recommend Apollo, Toledo and Bandit.

There are also St Victor types with pretty purple flags, including Blue (Bleu de) Solaise. They flower late, in early May.

In early April, these Haldor leeks were sown exactly a year earlier
Nine days later on 17th April after more leek harvests, garlic on the left; the leeks only have a few flower heads so far
At the spring equinox, a harvest of multisown Bleu de Solaise leeks

sow & propagate
Transplant - Size, time of year, Spacing, support
container growing
Prune and train plants/thin fruit
Harvest times and method
Potential problems


Allium roots leave lovely channels in the soil as they decompose, so most are good to stay there after your harvest. Like all decomposing roots, they provide food for soil organisms – just make sure not to leave any stem, which otherwise regrows little plants and flowering shoots.

Follow with

Leeks finish in the winter months and any vegetable can follow, except best give a few months break before replanting any alliums.

My mini rotation in the Three Strip Trial is potatoes –  leeks – potatoes – leeks and so on. We can eat potato and leek soup in winter, from the same bed in the same year. The Charlotte potatoes store until April – see Lesson 24 on potatoes.

A multisown leek harvest of 2.4 kg/5.3lb on 2nd April – the leeks were transplanted in August; now there is interplanted cabbage between leeks, to follow next, and sorrel plants are behind the parsley