Domakihub How to Grow Kohlrabi: From Seed to Harvest
Everything you need to get crisp, sweet kohlrabi bulbs from your garden, balcony, or grow bag.
Reviewed by Domakihub garden pros · 2026-06-23 · 5 min read
Kohlrabi is one of the easiest brassicas you can grow in a Greek garden, and its mild, crisp stems reward even first-time gardeners with a generous harvest. The video above walks through the complete growing process in a container — ideal for the balconies and compact outdoor spaces common in holiday rentals and urban homes across Greece. Read on for a step-by-step guide to soil prep, sowing, watering, and knowing exactly when to harvest.
Why kohlrabi suits Greek gardens and rental properties
Kohlrabi thrives in the mild shoulder seasons that Greece offers — autumn and early spring — when summer-scorching sun has either not yet arrived or just departed. This makes it a practical crop for home gardens, villa plots, and even hotel kitchen gardens aiming to serve fresh, hyperlocal produce.
Its compact root system means it grows happily in raised beds, grow bags, or medium-sized containers, so you do not need a large plot. A single 40-litre grow bag on a south-facing terrace can yield half a dozen bulbs.
Choosing the right variety
For Greek conditions, fast-maturing varieties (45–55 days) are the most reliable. Purple Vienna and White Vienna are widely available in Greek garden centres and online seed shops, and both handle brief warm spells without bolting as quickly as older heirloom types.
If you are growing for a holiday rental kitchen where aesthetics matter, the purple-skinned varieties add visual appeal to a crudité board, while the white-skinned ones tend to be slightly milder in flavour.
How to grow kohlrabi: 5 key steps
- 1
Prepare your soil or growing medium
Kohlrabi prefers loose, well-draining soil with a pH between 6.0 and 7.0. Mix two parts general-purpose compost with one part perlite or coarse sand to prevent waterlogging, which is a common problem on Greek clay soils. If growing in the ground, break up the top 20 cm and work in a handful of balanced granular fertiliser per square metre before sowing.
- 2
Sow seeds at the right time
In Greece, sow kohlrabi seeds outdoors from late August to October for an autumn–winter harvest, or from February to March under light fleece for a spring crop. Sow seeds 1 cm deep in rows 25 cm apart, or scatter them thinly in containers. Seeds typically germinate within 5–8 days at temperatures between 10 °C and 25 °C.
- 3
Thin and water consistently
Once seedlings reach 5 cm in height, thin them to one plant every 15–20 cm so bulbs have room to swell without competition. Water regularly but avoid saturating the soil — aim to keep it evenly moist. Irregular watering (dry spells followed by heavy irrigation) causes the bulbs to crack, so consistency matters more than volume.
- 4
Feed and manage pests
Apply a dilute liquid nitrogen fertiliser (e.g. fish emulsion or a balanced NPK liquid feed) every two weeks until bulbs begin to form, then switch to a low-nitrogen, higher-potassium feed to encourage swelling rather than leaf growth. In Greece, the main pest threats are aphids and cabbage white caterpillars; cover plants with fine mesh netting and check the undersides of leaves weekly.
- 5
Harvest at the right size
Kohlrabi bulbs are at peak sweetness when they reach 5–8 cm in diameter — roughly the size of a tennis ball. Waiting longer causes the flesh to become woody and bitter. Twist or cut the stem at soil level, strip the outer leaves, and use within a week. Younger, smaller bulbs can be eaten raw; larger ones benefit from roasting or steaming.
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FAQ
- Can I grow kohlrabi in a pot on a Greek balcony?
- Yes. Choose a container at least 30 cm deep and 40 cm wide, fill it with a compost-perlite mix, and sow 3–4 seeds per pot. Thin to the strongest two plants. Balcony pots dry out quickly, so check moisture daily in warm weather and water before the top 2 cm of soil feels dry.
- What temperature does kohlrabi need in Greece?
- Kohlrabi grows best between 10 °C and 25 °C. In most parts of Greece this window falls in autumn (September–November) and early spring (February–April). Sustained temperatures above 30 °C cause bolting — the plant sends up a flower stalk and the bulb turns woody — so avoid summer sowing on the mainland and islands.
- How do I stop kohlrabi bulbs from cracking?
- Cracking is almost always caused by uneven watering. The bulb swells rapidly after rain or heavy irrigation following a dry period, splitting the skin. Mulching around the plants with straw or compost helps retain moisture and buffer soil temperature, and watering little and often is far better than occasional deep soaks.