[Anton]

Greetings Gardeners.

My Chinese cabbages, which are really quite small but were growing well until two days ago, have now produced some little yellow flowers. Is that the end of my cabbages?

Anton

[madcat]

Still good to eat ...  but they aren't going to grow anymore.  So what are you going to have with your stir fried greens for dinner tonight?

[mumofstig]

yes, they've bolted 

[Anton]

Thanks for your answers. I think I will eat them with the new potatoes  I picked yesterday.

Anton

[crh75]

They need to be kept fairly damp and somewhat shaded from strong sun to have the best chance of success.  Sowing later in the year helps. 

Hope you enjoy them.

[JimB]

.
The only time I had success with them was when I sowed around late August time, so I have stopped trying to grow them!

The following has been taken off the net, hope it is of some use for you!

Planting time. Chinese cabbage is a cool-weather plant which will bolt and go to seed quickly in warm weather and long days; grow Chinese cabbage in spring or autumn in temperatures ranging from 45° to 75°F. Sow seed 4 to 6 weeks before the average date of the last frost in spring. Sow seed directly in the garden; seedlings transplanted into the garden may be shocked into bolting to seed. In mild winter regions, plant Chinese cabbage in late summer or autumn for a late autumn harvest.

http://www.harvesttotable.com/2009/02/how_to_grow_chinese_cabbage/