Makes a head somewhat looser than that of usual cabbage; sometimes called celery cabbage. Raw or cooked, it has a more delicate flavor than cabbage. There are three kinds: Michihi types (pe-tsai), with tall, narrow heads; Napa types (wong bok), with short, broad heads; and loose-head varieties (pak choy).
Favorite Michihli selections are 'Greenwich' (50 days to maturity) and open-pollinated Michihl itself. Among Napa varieties, try 'Minuet' (48 days), 'Rubicon' (52 days), and the miniature 'Tenderheart' (50 days). To sample a loose-head type, look for 'Tokyo Bekana' or the purple-leaf type. All are prone to bolt in hot weather if planted in spring; they make a better fall or winter crop. In colder-winter areas, plant seeds in ground in July; in milder climates, plant in August or September.
Sow seeds thinly in rows 2212 ft. apart; thin plants to 1122 ft. apart.
To prevent a buildup of soil-borne pests, plant in a different site each year. Club root is a serious fungal pest in acid soils; apply lime, if necessary, to raise the pH to at least 6.5. Floating row covers do a good job of controlling insects such as cabbage loopers, cabbageworms, cutworms, and root maggots. You can also control cutworms and root maggots by ringing the base of the plant with a cardboard collar. Bacillus thuringiensis (Bt) and spinosad applied according to label directions controls cabbageworms and loopers.