Brassica oleracea var. sabellica
Kale
Common names: Curly kale, Borecole
At a glance
- Light
- Full sun
- Spacing
- 50 cm, rows 60 cm
- Lifespan
- Biennial
- Sowing
- May–Jun
- Harvest
- Jan, Feb, Nov, Dec
- Hardiness
- Hardy down to −15 °C
- Water need
- Medium
Photo: Agnieszka Kwiecień, Nova · CC BY-SA 4.0 · Source
Description
Kale is the winter powerhouse in the bed and tastes best after the first frost, when the starch turns into sugar. Curly cultivars such as ‘Halbhoher Grüner Krauser’ or the tender palm kale relatives supply vitamins deep into winter. Frosty nights are what make it really mild.
Care instructions
Sow it from May (week 19) and plant the strong young plants out from July (week 28) with generous spacing. Hill the tall plants up slightly so they stay upright. From November (week 45) always harvest the lower leaves first, then it keeps growing from the top.
The care notes were machine-translated from German.
Garden year
SowingMay–Jun
HarvestJan–Feb, Nov–Dec
Germination
- Soil temperature
- from 5 °C, ideally 20 °C
- Days to sprout
- 4 to 10 days
- Light
- Sprouts in light or dark
- Sowing depth
- 1 cm
- How to start
- Start indoors, then plant out
Soil & site
Soil pH
Soil type
loamy, humus-rich, nutrient-rich, well-drained
Kale likes deep, loamy, humus-rich soils with good water and nutrient retention; it does not tolerate waterlogging, so the subsoil should be free-draining. On light sandy soils, compost worked in helps. Keep the pH in the neutral to slightly lime-rich range (around 7), which helps prevent clubroot; on soil that is too acidic, apply lime in autumn.
Brassicas are heavy feeders and prone to clubroot; keep to a 4-year break and do not follow directly on from other crucifers such as radishes or mustard.
Feeding
Heavy feeder
Months
Mar–Jul
In spring before planting, work mature compost and horn shavings shallowly into the soil. This is the basic supply for the season. Unlike head cabbage, kale keeps producing new leaves and needs an even supply of nitrogen; an organic top-up during the main growth phase (May to July), for example with nettle liquid feed, makes sense. Work in horn shavings by the end of August at the latest, so that they are broken down before winter and no nitrogen is washed out.
Overwintering
Kale stays in the bed all winter and survives down to about -15 °C in Central European lowlands without protection; frost even makes it sweeter. Harvest bit by bit from the outside in, and only in severe, lasting frost can you lay brushwood or horticultural fleece loosely over it.
Propagation
Methods
- From seed
In a home garden you propagate kale almost exclusively from seed. Vegetative methods play no useful role. You have two options: raising young plants first, or sowing directly.
Raising young plants (recommended): From April, sow into pots or seed trays, about 1 to 2 cm deep. Keep the soil evenly moist; in warm temperatures the seeds germinate within about a week. Continue growing the seedlings cool and bright so they do not become leggy. Once the young plants are 10 to 15 cm tall and have several true leaves (after about 4 to 6 weeks), plant them out in the bed.
Direct sowing: From mid May until August you can sow straight into the open ground, about 1 to 2 cm deep. After emergence, thin to 40 to 50 cm apart in the row, with 50 to 60 cm between rows.
Choose a sunny to partly shaded spot with nutrient-rich, deep soil. Kale is a long-season crop and very frost-hardy (down to about -15 °C). Harvesting begins in autumn and carries on into winter. Contrary to what is often claimed, kale does not need frost: cool temperatures alone make the plant convert starch into sugar, which gives it its mild flavour. Frost is therefore not strictly necessary, but it does no harm either.
Your own seed: Kale is biennial and only flowers in its second year. It is cross-pollinated: if you want seed that comes true to variety, let several plants of the same variety flower together and keep away from other flowering brassicas. F1 hybrids are not suitable for saving seed that comes true.
Companion planting
Good neighbors
legume family (Fabaceae)
particularly well establishedLeguminous plants collect nitrogen in the soil, from which Brassicaceae benefit as heavy feeders.
For example Bush beanPole beanBroad beanSnow peaWrinkled peaRunner bean and 35 more species in the catalogue
Source: classic companion planting (DACH-Gartenpraxis)
carrot family (Apiaceae)
You can pair celery and dill with all Brassicaceae because they repel the cabbage whitefly with their scent, a proven companion.
For example CarrotCeleriacDillParsleyFlorence fennelCoriander and 21 more species in the catalogue
Source: Bio-Gärtnerei Mixed-culture Practice
mint family (Lamiaceae)
You will notice that the intense scent of basil, thyme, and others confuses the cabbage whitefly and keeps it away from the cabbage family.
For example LavenderThymeBasilRosemarySageHyssop and 43 more species in the catalogue
Source: bio-gardening intercropping practice
nasturtium family (Tropaeolaceae)
Nasturtium serves as a trap plant for you. Aphids and cabbage whiteflies prefer it over the brassicaceae next to it.
For example NasturtiumMashua
Source: Trap plant practice in organic horticulture
Companion planting is partly traditional gardening lore. Where the reason is known, it is given.
Some of these explanations were machine-translated.
For signed-in gardeners
Sign in to see symptoms, severity, season and prevention for every one of your plants.
Free account, set up in 30 seconds.
For your garden
Grow Kale yourself
Gartenkern tells you when frost is coming, when to sow and when to harvest, for your location.
Free, no time limit
Notes from real gardens
What other gardeners have written down about this variety, anonymous and voluntary.
No notes shared yet. Will you be the first to write one down?
From the magazine
Harvesting Winter Vegetables: Fresh from the Frost
Kale, Brussels sprouts, corn salad and parsnip stand in the bed all winter and taste even sweeter after frost. Here is how to harvest fresh from the snow without the leaves turning to mush.
December: The Garden Sleeps, the Plan for the New Year Grows
In December the garden rests under frost and snow. You harvest the kale for the holidays, shake the snow off the branches, feed the birds, and over a cup of tea let next year's garden start taking shape in your head.
Kale: why frost makes it sweet
Kale is the most honest winter-vegetable classic: winter-hardy, healthy and fresh when other beds are empty. What really happens with the cold stimulus, why a hard frost is not necessary at all, and how to crop it from the bottom up from planting to winter harvest.