Modern Brussels sprouts are heavy cropping, mild flavoured and crop for several months in winter.
Absence
of good firm sprouts and a tendency for tall plants to fall
over or lodge are the commonest complaints. This is almost
always associated with the use of cheap open-pollinated cultivars
instead of the more costly but very reliable F1 hybrids such
as 'Bosworth', 'Romulus', or 'Revenge'.
Loose soil or excessive nitrogen fertiliser are commonly, but wrongly, blamed for fluffy sprouts. Drawing soil around the plants to 25cm (10in) up the stems as the plants grow in late summer and early autumn often eliminates the need to stake the plants.
Leaf diseases often lead to severe leaf loss in wet seasons and districts. Growing the plants at a wider spacings on open sites will reduce the severity of attack. There are no fungicides approved for home use for controlling these diseases. Some cultivars are resistant such as 'Bosworth' (ringspot) and 'Lunet' (white blister) and should be used where disease is severe.