I used to take it as gospel that any frost would cause most Bok Choy to bolt. But that turns out not to be the case.
Chinese cabbage is said to like the shortening days of Fall better than sporing. In most places, if you want spring Chinese cabbage, you have to start it indoors and plant out after frost.
One thing about starting Bok Choy indoors: all the other seeds get jealous when they see how fast Bok Choy sprouts and grows!
