Sorry for the delay this week – technical problems.
If you have Chinese cabbage in your hoophouse, January is the month to harvest it in zone 7. We do not harvest leaves from this crop, but wait for it to form full-size heads and then harvest those mature plants. We sometimes start harvesting as early as December 4, if the plants have reached full size and we “need” to harvest them. Otherwise we wait till December 15. If we have planted enough we can harvest until January 23, or sometimes as late as February 9.
Other Asian greens we are also harvesting at this time of year include pak choy, mizuna and the frilly mustards, tatsoi, Senposai, Tokyo Bekana, Maruba Santoh and Yukina savoy.
Chinese cabbage has very tender, light green savoyed leaves and is excellent for stir-fries, or pickling (sauerkraut or kimchee).
Chinese cabbage (both the Napa kind and the Michihli or Michihili kind) are Wong Bok types (Brassica rapa var. pekinensis) along with the “celery cabbages” – the non-heading Tokyo Bekana and Maruba Santoh.
We like Blues, an open-pollinated “barrel-shaped” Napa cabbage, shown in the photo above. Kasumi has the best bolt tolerance and is larger: 5 lb (2.3 kg) compared to 4 lb (1.8 kg); Orange Queen is a colorful but slower-growing variety (80 days in spring).
The Michihili types are taller and narrower, can be transplanted closer (8″) and might make more sense in terms of space use, although Napa cabbages do store better under refrigeration than michihli types. Jade Pagoda and the O-P Michihli both take 72 days from sowing to harvest in spring – considerably slower than Napa types. Michihili are more stress tolerant and resistant to bolting and black speck than Napa cabbage.
Blues takes 52 days from sowing to harvest in spring, but of course, takes longer in fall and winter. We sow September 15 in an outdoor nursery seedbed, and transplant into our hoophouse at 2-3 weeks old (October 2). It is very fast-growing in those temperatures and conditions. If we start harvesting December 15, it’s 3 calendar months from sowing, 91 days. The minimum germination soil temperature for Chinese cabbage is 50F (10C), and the ideal soil temperatures are 68F (20C) to 86F (30C). Under the ideal conditions the seedlings will emerge in 4 days. The maximum soil temperature to get any germination is 95F (35C).
We plant 52 plants for 100 people, with 4 staggered rows in the 4ft bed, 10.5″ apart (every 7th tine on Johnny’s row marker rake) and plants 10″ apart. With a harvest period of 5-8 weeks, 6-10 heads per week is about right for us.
We have not had many disease or pest problems with our hoophouse Chines cabbage. We do pay attention to using insect netting over the outdoor seedbed in the fall, but once we transplant indoors, our pest troubles are usually over. Vegetable weevil larvae have caused trouble in January. They come out of the soil at night and make holes in the leaves. They tend to prefer pak choy and turnips. We have used Spinosad against them with some success.
Tipburn (brown leaf margins, including internal leaves) is caused by quick drying of the soil, when the weather makes a sudden switch to bright and sunny from overcast. Be ready to irrigate when the weather suddenly brightens.
The winter-kill temperature of Chinese cabbage outdoors without protection is 25F (-4C). Our hoophouse crop has taken outdoor temps of 8F without inner rowcovers, and -8F with added thick rowcover. It is more cold-hardy than most varieties of pak choy, and less cold-hardy than Komatsuna, Senposai, tatsoi, Yukina savoy. Mizuna, Maruba Santoh and Tokyo Bekana have a similar level of cold-tolerance.
Once past the winter solstice, the order of bolting of Asian greens is something like: Tokyo Bekana and Maruba Santoh, pak choy, Chinese cabbage, tatsoi, Komatsuna, Senposai, mizuna, Yukina Savoy, leaf radish, frilly mustards.
When it’s time to harvest, we lever and pull the plant out of the soil, then cut off the root. This helps with the next task of replanting the space. It is much easier than cutting the plants at the base and then digging up the root.
After the Chinese cabbage are all cleared, we might follow with kale or collards on January 24 to transplant outdoors as bare root transplants in March. If we have no plans for a follow-on crop that early in the year, we fill gaps in the Chinese cabbage plot until January 25, using “filler” Asian greens we sowed in October. After that date we fill all gaps with spinach transplants until February 20, and from then on we only fill gaps on the edges of beds, leaving the bed centers free for tomatoes, etc in mid-March.
- Grow Your Own Chinese Vegetables, Geri Harrington, 1984, Garden Way Publishing. Includes the names for these crops in different cultures.
- Growing Unusual Vegetables, Simon Hickmott, 2006, Eco-Logic books, UK.
- Oriental Vegetables: The Complete Guide for the Garden and Kitchen, Joy Larkham, revised edition 2008, Kodansha, USA
- The Chinese Kitchen Garden: Growing Techniques and Family Recipes from a Classic Cuisine, Wendy Kiang-Spray
- Kitazawa Seeds and Evergreen Seeds have the most choices.
- Evergreen has a helpful clickable list.
- Fedco Seeds and Johnny’s have a good range.
- Wild Garden Seed has many interesting home-bred varieties. Search under Mustard.
- Even’ Star Farm Ice-bred Seeds
- ATTRA Cole Crops and Other Brassicas: Organic Production