Sow outdoors in mid spring in a well prepared seed bed. Soak the seeds for 48 hours in warm water before sowing 5cm (2in) deep, 8cm (3in) apart in drills 30cm (12in) apart. Germination is slow. Seeds can also be started off under glass.
When large enough to handle thin out seedlings to 30cm (12in) apart, and grow on for a season, the following spring (late March/April) transplant to a well prepared, deeply dug bed to which plenty of well rotted compost has been added. Rows 1.2m (4ft) apart, plant 46cm (18in) apart in the rows. Plant carefully making sure the roots are not cramped.