Sow under cloches or fleece or in a coldframe, thinly 13mm (½in) deep in a seed bed in rows 15cm (6in) apart from early-March to early-April, using early and late cultivars. Sow early for the best crops. Thin seedlings to 7.5cm (3in) apart. Raise plants in pots where clubroot is a problem.
For early crop sow under glass in small pots or cell trays in February, for harvesting from August.
From mid May to early June, when the young plants are 10-15cm (4-6in) high and have seven true leaves, transplant to their growing positions, leaving 60cm (2ft) between plants and 75cm (2½ft) between rows. Before planting, water plants well and water well again after transplanting.
Choose a sheltered, sunny site, protected from strong winds.
Any garden soil in full sun is suitable. Add up to two bucketfuls of well-rotted manure per square metre, and before planting or sowing add 150g (5oz) per square metre/yard of Growmore or other general purpose fertiliser.
Water every 10-14 days in periods of dry weather. Plants benefit from a top-dressing of high nitrogen fertiliser such as dried poultry manure pellets at 150g (5oz) per square metre/yard in July.
Mound soil around the base in September to support the plants.
Club root: Roots become swollen and distorted, and leaves become pale and yellow and wilt easily. Plants may die.
Remedy: Improve drainage and add lime to make soil more alkaline. Do not grow in affected soil.
More info on Club root
Birds: Birds, especially pigeons, can cause an array of problems including eating seedlings, buds, leaves, fruit and vegetables.
Remedy: Protect the plants from birds by covering them with netting or fleece. Scarecrows and bird-scaring mechanisms work for a while, but the most reliable method of protection is to cover plants with horticultural fleece or mesh.
More info on Birds
Cabbage root fly: White larvae approximately 5cm (2in) long, feed on the roots just below the soil surface, stunting growth and causing plants to wilt and die.
Remedy: Grow under insect-proof mesh or horticultural fleece. Seedlings are most vulnerable.
More info on Cabbage root fly
Caterpillars: A number of caterpillars will feed on brassicas, but the most common are those of cabbage white butterflies. You will usually see the caterpillars, if not, you will see the holes they make in the leaves. They will also bore into the heart of cabbages.
Remedy: In mild attacks, or if you have only a few plants, you may be able to pick the caterpillars off. Insect-proof mesh or fine netting (5-7mm mesh) can prevent egg-laying.
More info on Caterpillars
Early varieties can be harvested from August. Start from the lowest sprouts, when they are tightly closed, firm and the size of a walnut. Snap them off with a sharp downward tug. The flavour is improved once the sprouts have been frosted. At the end of the season the sprout tops can be harvested and eaten.
Early to mid season. Good crop of dark green, solid, round sprouts.
‘Maximus’ AGM:Early to mid season. Uniform plants with mid to dark green, smooth, dense sprouts.
New, clubroot resistant, mid-season, good crop of well-formed, tasty sprouts.
‘Diablo’ AGM:Mid to late season. Vigorous and tolerant of poor soils, smooth round, mid to dark green sprouts.
‘Revenge’ AGM:Very Late. Vigorous and tolerant of poor soils, with high yields of nutty flavoured sprouts; it stands well. Well spaced, easy-to-pick sprouts. Stands well and retains quality until February or later.
‘Bosworth’ AGM:Late. Oval sprouts, which are dark green, solid and closely spaced, so easy to pick. Stands well and retains quality until February.