Direct seed as soon as soil can be worked or start indoors 5-6 weeks before frost and plant out when plants are 4-5 weeks old. Sow seed .5 cm deep and 8 cm apart. Thin plants to 20-30 inches for early heads. You can direct seed in summer for a fall crop. Provide lots of fertility and even water for unchecked growth. Use floating row covers to protect plants if flea beetles are a problem.