Leeks all bolting

[Jimmy]

About 90% of my leeks have bolted.
Any reason.
Is there a bolt resistant variety.

Thanks Jimmy

[Penellype]

The most common reason for leeks bolting is sowing/planting out too early, when it is still cold. Although most leeks are hardy they are biennials, flowering naturally in spring. If they are planted out early and there is a cold spell they may behave as though that was winter and switch to forming flower stalks rather than leaves. This year April and May had well below average temperatures with some late frosts, so this would appear to be a likely cause. Another possibility is too much nitrogen in the soil.

I grow Oarsman, which is somewhat resistant to bolting, but being F1 the seeds are much more expensive than older varieties such as Musselburgh.

[Snoop Puss]

Jimmy, what variety did you grow and when did you sow them?

Interested to read your comment, Penellype. I know people tend to sow leeks very early and usually I buy plug plants. But this year I've grown three varieties, one summer (Chef's White) and three winter (Titus, Below Zero and Stocky), sown on 10 April. Sown three to a cell and planted out as a clump about 30 cm apart. They've all done much better than I expected, especially the Chef's White and Titus, neither of them F1 apparently.

[rary]

As Penellype has said low temperatures can trigger off bolting but I have also found irregular watering can cause this as well, I have also came across a reference to onions bolting, when one starts to bolt the stalk should be removed as soon as possible, as the bolting stem gives off pheromones which activates others to bolt, I would think that as leeks and onions are of the same family the same thing will happen with leeks, if you lift your leeks, remove and discard the central hard core and freeze the rest

[Purple Primrose]

Good research results on bolting and symptoms of allium diseases and deficiences can be found here:
https://projectblue.blob.core.window...rs%20guide.pdf
It includes lots of photographs to aid identification of problems.

[Jimmy]

They were "below zero" and "lyon prizetaker" both bolted as bad.
They were sown in seed trays and transplanted out when about 5inch tall.
Not sure of date but probably early. Will look at label when I get out but often text gets worn away.

Jimmy

[Jimmy]

Labels were faded but I think I could make out 25/4
Would be sown date.
Jimmy

[ameno]

They were "below zero" and "lyon prizetaker" both bolted as bad.
They were sown in seed trays and transplanted out when about 5inch tall.

That seems quite large for transplanting leeks. I feel that may also be part of the problem. Certainly with onions sets, the larger the set, the more prone they are to bolting, so leeks may be subject to something similar.
My leeks are usually like grass when I transplant them, maybe 3-4 inches tall.

[Snoop Puss]

Interesting. I sowed my Below Zero on 10 April and would have planted them out at biro refill kind of thickness, not sure when though. Plus we've had very variable temperatures this year. Very warm June followed by a week in July when night-time lows were around 6 ºC, followed by ten days in August or so of mid to top 40s during the day and mid to top 20s at night. So hard to know what kind of effect variable temperatures has. One thing that is different for me this year: I multisowed them, three to a module, and I didn't plant them very deep. Thick layer of muck on the surface in the Charles Dowding manner. Not sure if there's anything to be learned from that, but just sharing the info.