Plant 12 inches apart and top them (break off the growing tip) in early September for larger sprouts.
“They are a delicacy not surpassed by the finest cauliflower,” asserts the 1915 Salzer catalog. A real key to success is to top the plants around September 1. When I experimented by topping some and leaving others, the difference was dramatic. Within two weeks the topped plants were putting all their energy into making sprouts while the untopped plants continued to shoot up.