Recurring problem with Calabrese seedlings

[john9159]

For three years I've been trying to grow Calabrese in my greenhouse; these would have then been taken to the allotments to grow.
Each time I try growing them, it is an inevitable certainty that they will flower long before the planting stage.
What is the correct way to start these off so I can avoid this problem?
Thanks

[Chestnut]

I am no expert, having only attempted calabrese twice...
However, I have often read that various brassicas are ‘cold weather plants’, and noticed that mine all flowered at 6 inches high this year (when we had a warm spell), but grew Oklast year. I grew both outdoors (in seedtrays on an old plastic table with copper tape on the legs, to keep them away from slugs!).

So, maybe they don’t like it too warm?

Why not try putting some outside in a shady place next year, and see if they fare any better?

[Penellype]

Definitely sounds like they have bolted because they were too hot. Give calabrese plenty of shade and put it outside as it won't like being in a greenhouse, particularly in this hot weather.