This guide deals with Turnips
, Kohl Rabi
, and Celeriac
and Kohl Rabi
, although root vegetables, are actually part of the brassica family and as such have similar needs to caulis and cabbages.
Soil & Growing Position
All brassicas prefer a reasonably sunny spot and firm, free draining rich ground so dig in some organic matter such as Farmyard Manure or compost, ideally during the winter prior, to allow the soil to settle and consolidate as brassicas dislike loose soil and freshly manured soil. Mulching around the growing plants will help to retain moisture. Remember to plant any veg of the brassica family in a different patch of soil each year to stop the build-up of diseases such as clubroot (see Soil Preparation and Crop Rotation). If you have acidic soil, add in some lime during the winter as this will also help to control clubroot, which prefers acidic conditions. You can test your soil’s acidity by using a Soil Testing Kit. Apply a general fertiliser to the soil a couple of weeks prior to sowing or planting.
Sowing from Seed
For Kohl Rabi, sow green varieties between March and June and purple varieties in July/August. For Swede, sow from mid May to mid June. Early variety turnips are sown during March to June although Purple-top Milan can be sown during February under cloches. Maincrop turnips are sown from mid July to mid August and for turnip tops, sow a maincrop variety in September which will produce spring greens in March. The quality of turnips deteriorates with age so it is worthwhile successional sowing every two weeks.
Sow thinly at a half inch depth in rows 15” apart for swede, 12” for kohl rabi and maincrop turnips, 9” for early variety turnips and 3” for turnip tops only.
Growing On & Young Plants
Thin once the plants are large enough to handle. Thin in stages until the plants are 9” apart for swede and maincrop turnips, 5” apart for early variety turnips and 6” apart for Kohl Rabi. Turnips grown for the tops do not need thinning.
Brassicas are all susceptible to Cabbage Root Fly, which feeds on the roots, killing young plants. There are no chemical controls for this pest, although there is a nematode control. A traditional and effective control is cabbage collars, which are simply discs which you place around the base of the plant’s stem.
Periods of sustained dry weather will lead to small and woody roots and then cracking once the rain comes, therefore it’s important to water during dry spells to prevent either eventualities.
Hoe as usual to keep the weeds at bay.
should be levered out with a fork from early autumn, as they become large enough to use. You can leave them in the ground and lift as and when required up to early spring although it may be more practical to lift in December and store. Store swede by twisting of the leaves, placing in a box layered with dry peat or sand and then keep in a cool place such as a shed.
are harvested from May to September for early varieties and maincrop varieties are ready from mid October in mild areas and November for colder regions. Early varieties are pulled out of the ground like radishes rather than using a fork. They should be lifted when they are small, around the size of a golf ball if they’re to be eaten raw or a little larger if intended for cooking.
Maincrop varieties should be harvested once they are large enough to use and levered out with a fork. They can be left in the ground until ready for use. The roots can be stored in the same way as swede.
Turnips grown for their tops are ready in March/April. The tops should be cut off when they are around 5” high and the roots left in the ground to reshoot and provide further cuttings.
will be ready from mid July onwards and should be lifted once they are between the size of a golf ball and a tennis ball. Kohl Rabi doesn’t store so leave them in the ground and lift when ready for use, up to December.
is a popular veg on the continent but is little-known in the UK. As it’s name suggests, it tastes like celery and is delicious roasted, mashed, either on it’s own or mixed in with mashed potato.
Soil & Growing Position
Celeriac does need a well prepared plot and a sunny spot. Dig in the winter adding in lots of manure and apply Growmore 2 weeks before sowing.
Sowing from Seed
Sow in March, 2 seeds together in a compost-filled peat pot and raise under glass. Remove the weaker seedling and harden off prior to planting out in May/June. Plant seedlings a foot apart in rows 18” apart.
The plants will need watering well in dry weather. Apply a mulch in summer to aid moisture retention. Hoe as usual to keep the weeds down and feed occasionally. From midsummer, remove the lower leaves, exposing the crown and in September, draw soil around the stem base.
Unlike turnips, big is better as celeriac does not deteriorate in flavour or quality the bigger they become. Harvesting begins in October. If your site is exposed or your soil is heavy, lift all the roots in November and store them over winter using the method described for swede. Otherwise, they can be covered with straw and left in the ground to be lifted when required, throughout the winter into spring.