UK sowing calendar
When to sow leeks in the UK
Leeks sowing calendar (UK)
| Sow under cover | Feb-Mar (windowsill/greenhouse) |
|---|---|
| Sow / plant outdoors | Mar-Jun (in a seedbed) |
| Harvest | Oct-Apr (early types from Sep) |
Very hardy - leeks stand through winter frosts, making them a mainstay of the UK winter plot. Sow in a seedbed or modules, then transplant when pencil-thick (about 20cm/8in tall) in mid to late spring or early summer. Start indoors in late winter for an earlier crop.
UK timing runs on the last-frost date, not a USDA zone. Most of Britain sees its last frost around mid-May, with the north and exposed inland gardens a week or two later and the mild south-west and coast earlier. Tender crops start under cover and only go out once frost has passed; hardy crops can be direct-sown as soon as the soil is workable.
Timing aligned with the RHS grow-your-own guide for leeks.
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When to sow leeks in the UK — FAQs
When should I sow leeks in the UK?
Sow leeks under cover Feb-Mar (windowsill/greenhouse), then outdoors mar-jun (in a seedbed). Very hardy - leeks stand through winter frosts, making them a mainstay of the UK winter plot. Sow in a seedbed or modules, then transplant when pencil-thick (about 20cm/8in tall) in mid to late spring or early summer. Start indoors in late winter for an earlier crop.
Can you sow leeks outdoors in the UK?
Yes — sow or plant leeks outdoors mar-jun (in a seedbed). Wait until after the last frost (around mid-May, later in the north) for anything tender.
When is leeks ready to harvest in the UK?
Leeks is typically harvested Oct-Apr (early types from Sep) in the UK, depending on your sowing date, cultivar and region.
Is it too late to sow leeks?
It depends on the month and your region. Leeks has a UK outdoor window of mar-jun (in a seedbed); northern and exposed gardens run a week or two behind the south. Open Growli and tell it your postcode for timing tuned to your own last-frost date.