A taste of the weird and wonderful kohlrabi plant

Fiann Ó Nualláin offers a taste of the weird and wonderful kohlrabi plant EVERY time I see a kohlrabi (Brassica oleracea gongylodes).

A taste of the weird and wonderful kohlrabi plant

Fiann Ó Nualláin offers a taste of the weird and wonderful kohlrabi plant EVERY time I see a kohlrabi (Brassica oleracea gongylodes).

Every time I see a kohlrabi (Brassica oleracea gongylodes) I think of the Dutch painter Hieronymus Bosch, it’s such a fantastical looking plant that it should be in the corner of his painting The Garden of Earthly Delights. That said, weird is often wonderful and this little number is one you might consider to grow in your own real garden of earthly delights. An unusual gem, kohlrabi is flavourful, health-enriching and a visual delight — what more do you want?

Kohlrabi is a bit of an enigma — it translates as turnip cabbage yet it doesn’t quite taste of either. It is in the cabbage family and is sometimes referred to as a root vegetable, but it is not grown for its roots at all — which are not so palatable. It is grown for its swollen stem which is spherical and kind of “turnip-shaped”. The foliage tops are also edible so it’s a bit of a two for one. Gotta love that in any garden pressed for space.

There are white, green and purple varieties but all are similarly flavoured. The foliage is typical of greens and can be used as a cabbage or spinach but with a less distinct flavour or aroma — so it’s great if you don’t want to overpower tonight’s lasagna or tomorrow’s smoothie. The foliage is packed with vitamin C and often used raw or prepared into a coleslaw — or kohlslaw — and it’s not bad for pickling or fermenting either.

The stem which some call a bulb has a similar versatility it can be utilized raw or cooked. Raw it has a somewhat spiced but nutty-celery hint. Cooking brings out a sweetness and broccoli-like flavour but it can retain a radish-like or peppery undernote too. It can be cooked skin on or off. Traditionally boiled or steamed but it can be braised, barbecued, or even stir-fried.


I like to wait until May to sow Kohl Rabi, the seed packs often prompt April but we are generally out of frosty night territory by this weekend and I like to catch up with faster crops or tender crops from here on in. Kohl Rabi is not a fussy germinator and it’s quite easy to grow — but it does like a fertile site, it does preference full sun and attention to a watering regime is vital to flavour success; too dry or too wet for prolonged periods bitters up the bulb and foliage.

You can stager sowing up to mid-July to extend the harvest and not have a glut in one go 10 weeks after you first sow. In situ or into a seed tray, seeds can be pressed in about 1cm deep and should show signs of germination within a week or 10 days. Thin seeds or plant acclimatized seedlings to a spacing of 20cm-25cm — the aim is to harvest at tennis ball size (4cm-5cm) but foliage need room. The gap between rows is often recommended at 25cm-30cm apart.

Kohlrabi is generally not so affected by cabbage root fly or other brassica pests but it is good to think of a protective covering with a fine mesh to keep butterflies out and off. Any aphids can be hit with some homemade garlic spray. If you intend to include kohlrabi in your repertoire in future years then they will need to be figured into a brassica rotation plant to avoid club root and other pathogenic complications.

Health and nutrition

As a brassica the plant parts contain isothiocyanate and other glucosinolates which have been well researched in supporting human immune function and are potently antioxidant.

Their anti-inflammatory and antimutagenic properties have supplied their association with being chemoprotective and anticancer foods but interestingly those same isothiocyanates support the conversion of estrogen into less damaging forms — which apart from lessening oestrogen-driven cancers could be beneficial to any estrogen dominance side effects.

Like all other cruciferous vegetables, kohlrabi is a fine source of dietary fibre which not only supports gastrointestinal health but maximizes your nutrient uptake efficiency. So kohlrabi at a meal strengths the benefits of the other ingredients of that meal. Dietary fibre is also associated with better insulin sensitivity, better cholesterol control and even improved mood.

One of the hidden gems of kohlrabi is its benefits to eyesight — being a potent source of carotenes that nourish the function of the macula and retina and increase night vision potential and protect against macular degeneration. It doesn’t have to be all carrots and bilberry jam and you won’t have to squint so much at that Hieronymus Bosch.

Varieties to grow

There are more than 20 varieties that are readily available but here are some tried and tested for the Irish garden.

Azur Star is an early variety with a distinct purple skin. Trouble free. Delicacy Purple is both purple and a delicacy, trouble free.

Kolibri is a fast-maturing purple-skinned variety. Best harvested between golfball and tennis ball-size, it is slow to bitter up if left to mature longer.

Kossak is a pale green variety with is not known to bolt or go woody and as such is often grown into larger bulbs; not quite footballs but much larger than tennis ball.

Logo is a neat, white variety with good resistance to bolting.

Luna is a green skinned, early variety with good resistance to bolting.

Noriko is a pale green-skinned variety, pretty good bolt-resistance and fine yields.

Purple Danube is a sturdy and trouble free blue-purple variety.

Purple Vienna is a sturdy but neat purple-skinned variety, harvest small.

White Vienna is a white skin and flesh variety. Harvest small to medium.

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