Chinese cabbage refers to two different cool weather crops that lend themselves to Bay Area fall and winter gardens.
Chinese cabbages (Brassica rapa) are variations on the lowly turnip. The two subspecies we most commonly see are forms of Napa cabbage (var. pekinesis) and bok choy (var. chinensis). These healthful foods have been grown in China since before the 15th century.
Also known as Korean small cabbage or celery cabbage, Napa cabbage has a milder flavor than more domestic varieties, but it packs a nutritional punch that’s difficult to beat. According to a study conducted by the Centers for Disease Control in 2014, Chinese cabbage ranks second only to watercress as a nutrient dense food. Napa cabbages come in both head and loose leaf varieties. Napa cabbages can be planted in the Bay Area twice each year: first, February through April; and again, August through October.
Unlike the Napa cabbages, bok choy does not form heads. Bright white stalks give way to dark green blades, growing in a cluster, much like celery. Bok choy can be planted in the Bay Area in September and October, and then again, February through April.
How to grow Chinese cabbages
These biennial plants are generally grown as annuals. If you allow your plants to go to seed, you can create a seasonally perpetual crop within your landscape. To begin, find a location with full or partial sun and well-drained soil. Adding aged compost to the planting bed ahead of time can provide a nutritional boost to your plants and improve soil quality, while you’re at it. Chinese cabbages can also be grown in containers. Use pots that are 8 to 12 inches across and 18 to 24 inches deep. Seeds should be planted 1/2 inch deep and successful seedlings should be thinned to 12 - 18 inches apart. These plants do not transplant well, so it is better to put them where you want them right from the beginning.
Pests and diseases
Being closely related to broccoli and cauliflower, Chinese cabbage is subject to many of the the same pests: aphids, flea beetles, armyworms, loopers, cabbageworms, leaf miners, and millipedes. Common diseases include white rust, damping-off, yellow virus, clubroot, black rot, and bottom rot. Many of these diseases can be prevented by allowing soil to dry out between waterings.
Harvesting Chinese cabbages
Chinese cabbages are good candidates for succession planting. If you start one new plant per person every two weeks, through fall and winter, you will have an abundance to harvest. You can extend that harvest by only cutting away outer leaves on an as-you-need-them basis. These plants will continue to produce inner leaves through the growing season.
Like other cabbages, these plants to not produce a lot of ethylene gas. Ethylene gas is what makes fruits and vegetables ripen. Cabbages are, however, very sensitive to the ethylene gas produced by other plants, so it is a good idea to keep harvested leaves or heads in a plastic bag in the refrigerator. Or, your can always try your hand at fermenting some cabbage for your very own kimchi!
I hope this information inspires you to grow more of your own food. You can ask your garden questions on my Home page.