[Yorkie]

I have some strong looking Calabrese plants that should be planted out in March but already 4" tall!!!!  Do I need to slow them down somehow - they are in 3" pots in a cold greenhouse.

[mumofstig]

That's strange when were they sown? Calabrese are usually sown in Spring for Autumn picking and .

[Beepee]

Hi yorkie.
Yes, different I know. But the seeds are from Kings seeds - Calabrese F1 Hybrid Parthenon.  Quoting from the packet:

 "...Sow September to harvest June.  ...September sown seedlings should be grown on in  cold frame and plant out early March."
Beepee

[mumofstig]

A new idea, then, not yet shown on their website.
https://www.kingsseeds.com/Products/Vegetables/Calabrese/Calabrese-Parthenon-F1?returnurl=/Products/Vegetables/Calabrese&pn=1&ps=12&sb=NodeOrder&lm=grid_template&b=true

I can only suppose that it has been too warm for them in the greenhouse, although we did have some very cold nights a few weeks ago.
 
That leaves you with 2 options IMO 
1) pot them on when they need it, and let them carry on growing, maybe some cold weather will come along to slow them down.
2) plant them out under a cloche which will slow them down, but still give them protection from all but the worst weather.
Hope that helps.

PS
Suttons tells you to sow even later, in April to June
http://www.suttons.co.uk/Gardening/Vegetable+Seeds/All+Vegetable+Seeds/Broccoli+Seeds+-+F1+Parthenon_152282.htm#CMRTabs2

[Beepee]

OK Many thanks.  For now i will keep greenhouse open - while it stays mild - and my fingers crossed. But I will try potting them on if they get much bigger.  I will also keep this updated as to how they work out!!!
Cheers
.

[Beepee]

Oh...! Should this be a 'new' topic?

The calabrese sown last autumn are now looking splendid and I will be cutting the  first for Sunday lunch (tomorrow).  Good to win one now and again!

[Yorkie]

Excellent, great news and enjoy!!