Sea kale
Crambe maritima
A vegetable, planted March or May, or sown March to May or September to November.
In September: cut back the sea kale. It can be sown under cover now.
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Sea kale, month by month
Bar: the usual months. Sprout: this month.
| Sowing, planting or job | Sep | Oct | Nov | Dec | 2027Jan | Feb | Mar | Apr | May | Jun | Jul | Aug |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sow under cover. | usual | usual | usual | none | none | none | usual | usual | usual | none | none | none |
| Plant out. | none | none | none | none | none | none | usual | none | none | none | none | none |
| Plant a bare-root sea kale. | none | none | none | none | none | none | none | none | usual | none | none | none |
| Cut the sea kale shoots. | none | none | none | none | none | none | usual | usual | usual | none | none | none |
| Mulch the sea kale. | none | none | none | none | none | none | usual | usual | usual | none | none | none |
| Cut back the sea kale. | usual | usual | usual | none | none | none | none | none | none | none | none | none |
What to do, and when
The usual months for a UK garden. Your own plan gives the week.
Sowing and planting
Sow under cover March to May, and September to November, 1.2cm deep. Moderate sources: RHS and Chiltern Seeds.
Plant out in March, 60cm apart. Moderate sources: Gardeners’ World and Jekka’s.
Plant a bare-root sea kale in May, 2.5cm deep, 60cm apart. Moderate source: Marshalls.
Cut the sea kale shoots
Wait until its second spring in the ground.
Usually March to May. Moderate source: Marshalls.
Mulch the sea kale
Spread a thick layer of well-rotted manure or garden compost.
Usually March to May. Moderate source: Gardeners’ World.
Cut back the sea kale
Cut the plant down to ground level.
Usually September to November. Moderate source: RHS.
What the source words mean
Moderate: another trusted UK source, or the RHS on its group.
What not to do
Don’t move it
Plant sea kale where it is to stay: it doesn’t like being moved.
Moderate source: Gardeners’ World.
Every line above names the page it comes from. Where we found no good source for a job, we left it out. Where the name “Sea kale” comes from.