Kohl Rabi - is it a Root Vegetable?

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Some vegetables that will grow in a little shade

One of the most difficult things I get asked (and asked very frequently) is to suggest vegetables that will grow well in shady places. Such vegetables are rare!

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Kohl Rabi - is it a Root Vegetable?

For horticultural show purposes kohl rabi is certainly a root vegetable - it is included in the list of roots given in the RHS Horticultural Show Handbook . This despite the fact that the "root" is a stem which grows at least an inch above the ground! It is also included, however, in the list of salad vegetables on the same page-a versatile vegetable both in the kitchen and on the showbench.

Despite its versatility kohl rabi is seldom grown in gardens or allotments, and is not often seen at shows. Nonetheless well grown specimens, especially of the purple cultivars, make a striking exhibit and will always catch the judges eye in salad or "any other vegetable" classes. In the kitchen, used raw, it is a flavoursome salading and offers an alternative to turnip when cooked.

Kohl rabi is a brassica, also known as turnip rooted cabbage, and looks rather like a tennis ball with a tuft of leaves on top, all perched on a short stalk.

It is easily grown from seed and will mature in around twelve weeks - anything from ten to fifteen depending on the time of year and the weather. Seed can be sown in a nursery bed, or in situ, from March until July. My own practice is to sow seed of the open pollinated cultivars in an outdoor nursery bed but to raise seedlings of F, hybrid cultivars in a cold greenhouse, pricking them out into two inch pots at the two adult leaf stage. Seedlings should be set out six inches apart when about four inches high. Or thinned to the same distance when large enough to handle easily. The highest yields per unit area can be had by setting plants in a diamond formation, each one six inches all ways from its neighbours.

Any reasonable garden soil will produce a good crop and kohl rabi will tolerate dry conditions better than turnips. Indeed, many books and seed catalogues say it grows well in dry conditions. It will certainly tolerate dry soils, but it produces a far better crop in moist soil, or when well watered in dry years.

It will also tolerate some shade. In fact I normally grow it interplanted amongst Brussels sprouts, sprouting broccoli or kale, in fact amongst any tall brassicas. Put two or three kohl rabi between each sprout or broccoli plant and between the rows, and you will greatly increase the total yield per unit area. Set out the kohl rabi at the same time as you plant the others. If ground is cropped intensively in this way then a dressing of a general fertiliser should be applied some two or three weeks before the plants are set out. I use fish, blood and bone.

As a brassica you would expect it to be prey to all the usual brassica ills. It is, however a relatively troublefree crop.

Maturing in ten to fifteen weeks it is usually out before being seriously affected by club root. Wise growers will take precautions against cabbage root fly-but in my experience kohl rabi is seldom badly affected, the flies usually prefer other brassicas if they are available. Grey cabbage aphis may become a problem on the younger leaves if it is not spotted early.

Kohl rabi is always welcome in the kitchen. The bulbs can be used in any way you would cook a turnip. Most people would accept, however, that they are more delicately flavoured. Valuable as it is as a cooked root vegetable it is as a salad vegetable that kohl rabi really comes into its own. Young bulbs about two inches in diameter peeled thinly and then coarsely grated make a tasty and unusual, addition to summer or autumn salads. For use cooked the bulbs of F, hybrid cultivars can be harvested rather larger, up to four inches in diameter. It is usually wiser, however, to cut the older cultivars, 'White Vienna' and 'Purple Vienna', when they are between two and three inches.

It is as a summer crop that kohl rabi is best known. Nonetheless, the hardier cultivars will stand light frost and can be left in their rows until Christmas, at least here in the south east.

The various cultivars do differ in the amount of frost that they will withstand. By and large the hardiest cultivars are those with purple skins. 'Purple Vienna', an old, well loved cultivar is probably the hardiest of all. Of recent years there have been several new F, hybrids introduced. Of these I, myself, have found the purple skinned 'Blaro' and the two green skinned cultivars 'Lanro' and 'Rowell' very satisfactory. None of these, however, appear to withstand hard frosts.

This article originally appeared in the Members Bulletin, the journal of the National Vegetable Society, which is sent quarterly to members. You can Join the National Vegetable Society here

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