Also called napa cabbage, 'One Kilo Slow Bolt' has a delicate flavor, a soft texture in between that of lettuce and regular cabbage, and tight heads have a creamy yellow interior. Cabbage is most reliable when sown in mid- to late summer for fall harvest, although because this napa is quick to mature and slow to bolt, it's also a good candidate for spring sowing. Grows best at 60°-65°F.