PlantSowGrow
How to grow Kalettes (Flower Sprouts)
Brassica oleracea
A cross of Brussels sprouts and kale: tall stems covered in frilly green-and-purple mini kale rosettes from autumn to winter.
At a glance: Sow late February to late March, harvest from mid October.
When to sow, plant and harvest
Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.
Growing Kalettes (Flower Sprouts): what it needs
- Light
- Full sun · 6+ hours a day
- Watering
- Water regularly in dry weather
- Soil
- Fertile, well-drained soil
- Spacing
- 60 cm
- In pots
- Best in the ground
- Feeding
- A general feed before sowing or planting
- Harvest
- About 70 days from sowing
- Hardiness
- USDA zones 3–9
- Difficulty
- Easy
Step by step
- Late February – late March · 7 weeks before the last spring frost
Sow Seeds Indoors
Sow in modules or small pots of seed compost under cover. Sow 1 cm deep.
- 5–10 days after “Sow Seeds Indoors” · Early March
Check Germination
Seedlings should appear in 5–10 days. If sown outdoors, thin to 60 cm apart when big enough to handle.
- 14–21 days after “Check Germination” · Mid March – late March
Pot On Seedlings
Move seedlings into 9 cm pots (or keep in modules) when they have their first true leaves.
- Early May · 3 weeks after the last spring frost
Harden Off
Stand plants outside by day for 7–10 days before planting out.
- Mid May – mid June · 4 weeks after the last spring frost
Plant Out
Plant out 60 cm apart and water in well.
- 0–3 days after “Plant Out” · Mid May
Net Against Pests
Cover with fine insect mesh or netting straight after planting to keep off pigeons, cabbage white caterpillars and flea beetles.
- 30–60 days after “Net Against Pests” · Mid June – mid July
Firm In and Stake
Tread the soil firmly around the stems and stake tall plants against winter wind.
- Mid October – mid November · around the first autumn frost
Start Harvesting
Snap off the rosettes from the bottom of the stem upwards; frost makes them sweeter.
- 100–130 days after “Start Harvesting” · Late January – late February
Finish and Clear
Pull up the stems when picked clean and crush them before composting.
