1. Planting reason: If the moss of Chinese cabbage is not properly managed, not fertilized in time, or is short of water, it will affect the balanced absorption of nutrients by the roots of Chinese cabbage, hinder the growth of Chinese cabbage, and make it malnourished, so that Chinese cabbage will be bitter, especially near the stem base; In addition, the over-aged red cabbage moss will also make the edible part bitter because of its original growth path.

2. Variety reason: red cabbage and Guangdong cabbage are the same variety, and they are a variety subspecies of Brassica in Cruciferae. This kind of cabbage is generally slightly bitter, especially the leaves and epidermis near the stem are bitter, which is a common phenomenon.