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My whole pak choi spring harvest is bolting right now (I sowed in a green house very early to get a second one in if need be).

However I read that with pak choi when the plant is bolting it usually does not turn as bitter as other plants. I also read somewhere (I cannot find that source) that you can cut off the flower stem and the plant will continue as usual.

Has anyone here done that?

Sue Saddest Farewell TGO GL
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Hans
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  • Hi Hans! I've seen you around the network, and just want to welcome you here. I hope you stay around and have some fun! – Sue Saddest Farewell TGO GL Mar 26 '16 at 15:58
  • I did that once. The plants never did return to producing leaves for the head. Cooked some bolted ones and they tasted fine. – Wayfaring Stranger Mar 26 '16 at 16:59
  • Thanks. I'll take the meagre harvest I have so far and will replant them again - hoping for more success if I can plant them straight in the beds without transplanting. – Hans Mar 27 '16 at 17:06
  • I got mine in on March 3 this year. I'm hoping I'll finally get a good crop before it turns too warm and things go to heck. They grow the stuff commercially in Iowa now. I've no idea how the get into the fields early enough. Maybe they plant in the fall? Anyway, best new veggie since Jalapenos showed up in the early 70's. The stuff likes indoor growth chambers just fine, but $10 a month electricity for a veg that sells for $0.99 a pound in the stores is just ridiculous. – Wayfaring Stranger Mar 27 '16 at 17:50
  • I'm based in Scotland so probably a fair bit colder here. I followed advice from a Chinese Friend who said they've grown it in the green house over the winter. I've taken that as - then planted them out. But it seems they just placed them in larger containers inside. Should be about to sow them outside next month and in the meantime I'll try a larger pot in the greenhouse. – Hans Mar 27 '16 at 20:26

1 Answers1

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Bok choy is a cool season crop and bolting is triggered by lengthening photoperiods ( daylight hours exceeding 16 hours, or darkness less than 8 hours for a month ), and temperatures below 55 deg F ( 12 Deg C ). Once bolting has been triggered, the plant can not return to the vegetative stage. Short days with warm temperatures will prolong the vegetative stage.

Therefore unless you can artificially control lighting you should ensure your plants mature before they reach the critical photoperiods. This can be accomplished by planting several weeks after the summer solstice so that it meets lengthening hours of darkness.

Since your plants are bolting in Scotland in late March, when there are only 13 daylight hours that would suggest your problem was triggered by cool temperatures. The average temperature in March is 6 deg C, and in an unheated glasshouse may only be a few degrees more than that, and not enough to stop the bolting.

Edit: 24 May 2020

The author Joy Larkcom says Bok Choy needs to be germinated and grown at 18-22 C in its first month otherwise it bolts. Thereafter it tolerates colder temperatures. She also quotes a Rodale study that showed that Bok Choy grown at an average 10C bolted.

How to stop spring crops bolting

Specialty and Minor Crops Handbook, 2nd Edition by Claudia Myers

Oriental vegetables, Joy Larkcom 1991

Graham Chiu
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