Tony Dickerson answers your questions
QMy Christmas Brussels sprouts were tiny. Why?
Robert Bower, Addlestone, Surrey
ABrussels sprouts are a long season crop and if you want fine sprouts on your plate next Christmas, you need to start preparations now. First, you’ll get much better results with F1 hybrids. You get relatively few seeds for your money but a dozen plants should be more than enough for the average family. F1 varieties are also less likely to produce ‘blown’ sprouts, where they’re all leafy and fail to make tight buttons.
You also need to choose a mid-season variety that’ll produce harvestable sprouts by late December. Try ‘Brigitte’, ‘Brodie’, ‘Doric’ and ‘Trafalgar’. Sow them in early March for transplanting in April or May to achieve large, stronggrowing plants. The number of sprouts in the winter is directly dependant on the number of leaves made during the summer.
Brussels sprouts need very fertile soil to perform well. They do best on a good loam and will struggle on sandy soils. You’ll need to lime acid soils – ideally in the preceding autumn. Apply as much as 300g per sq m (10oz per sq yd) of Growmore in two lots – one third before and two thirds after planting. Equivalent quantities of other fertilisers can be used instead. Adding two bucketfuls per sq m (sq yd) of organic matter can replace half the fertiliser but don’t do this at the same time as liming.
When it comes to transplanting the plants, make sure they’re firmed in well. Plants should be at least 60cm (2ft) apart in the row. Allowing 90cm (3ft) between rows allows easy access for picking. Sprouts need moist soil in summer if they’re to grow well, with generous watering every couple of weeks in dry spells.
On windy sites you may need to stake individual plants. Alternatively, in late summer mound the soil up around the base of each plant. As well as netting to exclude cabbage white butterflies and pigeons, an occasional spray with SB Plant Invigorator will control aphids and offer protection against mildew and white blister. It’s also useful to clear away any yellowing lower leaves.
Once the sprouts start to swell it’s also a good idea to remove any small, weak sprouts on the lowest part of the stem. Remove the leaves as you harvest from the bottom.