If you like Cabbage, Mustard, Lettuce & Spinach, you might also like these Brassicas as cold-hardy salad greens:
- Komatsuna mild, cold-hardy, productive
- Tatsoi - very mild, cold-hardy, slower-growing
- Mizuna - medium mild, a little mustardy
Bok Choy and Chinese cabbage (Napa or Michihili) are less cold-hardy. They might not be good crops for mid-winter, but great for spring and Fall (avoid hot weather). Most Chinese cabbage varieties are better adapted as Fall crops in most climates.
Whatever is growing when heat or frost approach can be harvested and eaten at whatever age they reached, for example in salad. The smaller, the more tender and sweet! Seedling & baby leaf crops can be companion-grown (inter-cropped?) under taller crops. Or they can be planted with slower-growing crops and then harvested before the other crop gets big.
Both Bok Choy and Chinese cabbage will bolt in frost and Chinese cabbage may bolt after a week or two of coldish nights. Both are very mild in flavor. Young & baby leaves belong in salad, and you can steam or fry older leaves.