Brussel sprouts needs well consolidated, fertile soil, so leave several months between digging, adding compost and adding lime (dislikes acid soil) before planting. Pick a sunny, sheltered area (away from high winds)which has not grown brassica for a few years. Do not fork over, instead tread soil gently down and rake over the surface. Sow seeds thinly 12mm (½in) deep in rows 18cm (6in) apart. If the soil is dry, water well and allow to drain before sowing. Cover with soil. Thin seedlings to prevent them from becoming weak and spindly. They should be about 10cm (3 in) apart. Seedlings can be transplanted when they are about 15cm (6 in) tall. Water the rows the day before transplanting out.