How to grow Kohlrabi

Brassica oleracea · turnip cabbage, German turnip

A fast-growing brassica grown for its swollen, crisp stem with a mild, sweet taste. It grows best in cool, damp weather; cold spells make it bolt, and heat and drought make the stem woody.

Quick facts

Type	Vegetable
Family	Brassicaceae
Light	Full sun
Soil pH	6–7
Frost	tolerates light frost
Soil for sowing	from 10 °C
Germination	7 days
Seedlings ready	28 days
Sowing to harvest	55 days
Where it grows	Greenhouse, Open ground, At home

When to plant

Sow for seedlings about 5 weeks before planting out.

It tolerates light frost: plant out in open ground about three weeks before your last spring frost.

In an unheated greenhouse everything moves about three weeks earlier.

The first harvest comes about 55 days after the shoots appear.

Frost dates · When to plant

Care

Greenhouse

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	18…21 °C	—
Growth	every 3 days	10…24 °C	nitrogen, 21 days into the stage
Harvest	every 3 days	10…24 °C	—

Open ground

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	18…21 °C	—
Growth	every 4 days	10…24 °C	nitrogen, 21 days into the stage
Harvest	every 4 days	10…24 °C	—

At home

Stage	Watering	Temperature	Feeding
Seedlings	every 2 days	18…21 °C	—
Growth	every 3 days	10…24 °C	nitrogen, 21 days into the stage
Harvest	every 3 days	10…24 °C	—

Growing notes

Light

Needs full sun, at least 6 hours of direct light; some varieties cope with partial shade in summer.

Soil

Fertile, moisture-retentive, well-drained soil, pH 6–7. Lime soil below pH 6 to deter club root.

Care

Sow or plant out only once it stays above 10 °C, 15 cm apart. Keep the soil evenly moist, about 25 mm of water a week, as the roots are shallow and dryness makes the stem woody. Feed a little nitrogen three weeks after planting out or thinning; it needs less than other brassicas. Net against cabbage white caterpillars. Harvest when the stem is 5–7.5 cm across; larger ones turn tough and woody.

Pests and diseases of Kohlrabi

Sources

Figures checked against these sources.