KohlRabi Growing Guide: from seed to kitchen

How to Grow KohlRabi

The essential guide to growing kohl rabi from seed; with notes on germination, cultivation, harvest and even kitchen uses. One of the kookiest and grooviest looking vegies out there!!

Meet the Kohlrabies – Flavour & Kitchen Uses

Green / White-skinned – crisp, juicy and mildly sweet; grate raw for slaws, slice for crudités or dice into stir-fries.
Purple-skinned – same flavour as green but eye-catching colour that holds when lightly steamed; lovely roasted with herbs.
Giant / Storage types (e.g. ‘Kossak’) – bred for late-season harvest; dense flesh ideal for soups, mash or slow braises and stores for months.
Leaf use – young tops cook like kale or silverbeet; a bonus crop of tender greens.

Seeds per Gram: ~250 – 300 seeds

Germinating Temperature: 16 – 27 °C (emergence in 7 – 10 days)

Feed Requirements:

Moderate feeder.
Work 5 cm of compost plus a balanced organic fertiliser into the bed before sowing.
Half-way to harvest: apply a liquid seaweed or fish emulsion to keep stems swelling quickly.

Growing Notes:

Climate & Timing

Temperate & cool zones: sow late summer-autumn for spring harvest, or late winter-early spring for early summer harvest.
Sub-tropics: sow autumn-winter only; avoid humid summer heat.
Frost tolerance: mature plants handle –4 °C and taste sweeter after light frosts. Hot weather (>28 °C) slows growth and causes woody bulbs.

Sowing & Spacing

Direct-sow 5 mm deep, spacing seeds 10 – 20 cm apart in rows 30 – 40 cm apart; thin to strongest plants once true leaves show.
For transplants, start seed 4 – 6 weeks early; set out when seedlings have 6-8 leaves and nights stay above 8 °C.

Soil & Water

Prefers fertile, well-drained loam, pH 6.5 – 7.5.
Keep the top 5 cm of soil evenly moist.
Mulch to conserve moisture and suppress weeds.

Care

Net young plants to exclude cabbage white butterflies and pigeons.
Remove lower yellowing leaves to improve airflow.
Bulbs maturing in mid-summer become woody.

Common Problems & Fixes:

Woody or hollow bulbs: usually heat, drought or over-maturity – sow at the right time, water consistently and harvest young (5 – 7 cm for tender types).
Bolting: triggered by cold shock in seedlings or prolonged heat; harden off transplants, maintain steady growth, choose bolt-resistant cultivars.
Cabbage moth/caterpillars: exclude with insect mesh, hand-pick or spray dipel.
Aphids: hose off, or apply insecticidal soap; encourage ladybirds.
Slugs & snails: use beer traps or iron-based pellets, especially around seedlings.

Harvesting:

Harvest bulbs when 5 – 7 cm across for salad-grade tenderness, or up to 10 cm for cooking.
Cut just below the swollen stem, leaving the fibrous taproot in the ground.
Young leaves can be picked any time.

Storage & Use:

Trim leaves, then store bulbs in a perforated bag in the refrigerator for up to two weeks.
For long keeping, blanch cubes and freeze, or pickle thin slices in a light vinegar brine.

Give kohlrabi cool temps, steady moisture and rich soil, and this space-saving brassica will reward you with crunchy, apple-sweet stems and bonus greens through much of the year.