Flower Fruit stoped develop
 

Stoped at stage 4.
[IMG]https://www.greenhousesensation.co.uk/media/wysiwyg/Tomato_flower_4.jpg[/IMG]
[url]http://www.greenhousesensation.co.uk/flower-progression-and-fruit-development-on-our-costoluto-fiorentino-tomatoes[/url]

A lot of flowers not dropping but just stopped. What cause it searching for research, but cant find.
Is it for to much nitrgoen, low temperature, or else.