How to grow kohlrabi in Canberra region

Owen Pidgeon
Easy to grow: Kohlrabi can endure dry conditions.
Easy to grow: Kohlrabi can endure dry conditions. 

Kohlrabi is a strange-looking member of the brassica family with a bright purple or green skin and white flesh. It has been grown widely in northern Europe for at least 500 years and there's even a reference made by Pliny the Elder to such a vegetable back in the days of the Roman Empire. Nowadays it is commonly used in Indian and Asian cuisine as well as in traditional vegetable soups and stews.

The kohlrabi bulb, when its leaves are removed, looks like a Russian Sputnik satellite. Its name is derived from two German words that accurately describe its taste when boiled: kohl (cabbage) and rabi (turnip). It's highly nutritious and can still produce a harvest when rainfall is scarce. 

Quick-growing kohlrabi is not troubled by some of the problems associated with growing cabbages. It can be harvested in a little over two months when the bulbous stem is 6-7 centimetres in diameter (about the size of a tennis ball) before it gets too old and woody. Trim off the long leaves but leave the smaller, inner leaves to keep its freshness. 

Kohlrabi and cucumber salad.
Kohlrabi and cucumber salad. 

Purple Vienna is the well-known purple-skinned variety. It produces a flattened globe-shaped bulb. It can be sown both in spring for use over summer and in early autumn for a winter harvest. Harvest this variety when it is the size of a golf ball otherwise it will become too fibrous if left in the ground for too long. White Vienna has pale green skin and has a delicate, mild flavour.

Kohlrabi will grow well in shallow soils, as the swollen bulbous part of the plant grows just above the soil surface. You can also use large pots and grow it on a balcony along with some silverbeet and leafy salad greens. Keep the plants well watered and feed them every two weeks with a complete liquid fertiliser. 

Kohlrabi will store well in the fridge for up to two weeks. Alternatively, they can be peeled and diced then frozen for later use.

To add slices to a salad, blanch it first. Its crunchy texture adds a dimension to many dishes. To roast kohlrabi, steam the bulb first for 4-5 minutes then roast for about 45 minutes in a medium oven. The fleshy bulb soaks up cooking juices just like turnips so it's  a wonderful vegetable to serve with roast duck or chicken.

The leaves are also tasty when the plant is small and tender. Saute in butter with garlic and chilli powder, or steam as you would cabbage leaves.

Kohlrabi and cucumber salad

400g kohlrabi
2 cucumbers
1 large carrot
2 spring garlic
2 tbsp hot chilli sauce
1 tsp salt
2 tbsp rice vinegar
1 tbsp sesame oil
juice of 1 lime
1½ tbsp fresh coriander, finely chopped

Peel the outer skin of the kohlrabi and grate the flesh. Grate the cucumbers and carrot. Finely chop the spring garlic, both leaves and small bulb. Mix all the vegetables together in a bowl and add the chilli sauce. Sprinkle with salt and allow to stand for 30 minutes. Drain off any excess liquid. Then mix in the rice vinegar, sesame oil, lime juice and coriander. 

This week in the garden

Plant out quick-growing bush beans, cucumbers and beetroot directly into garden beds with a good level of added compost.

Keep planting a selection of herbs, including basil, coriander and chervil.

Now is the traditional time for planting out tomato, capsicum and eggplant seedlings into your garden. Remember that these plants need to have night-time temperatures of at least 12 degrees for strong flowering and fruit setting.

Plant rockmelon and small watermelon varieties into planting circles that have been filled deeply with old compost and other aged organic matter. 

Provide giant snow pea varieties and climbing beans with good support frames and keep them well watered. Daily picking of these vegetables will promote further flowering. 

Check for slugs among strawberries and soft leaf salad vegetables, and remove by hand. Mulching strawberries with pine needles will provide a deterrence and ensure the berries are clean when harvested.   

Owen Pidgeon runs the Loriendale Organic Orchard near Hall.