Sad broccoli plants

Started off two sets of broccoli for next spring and was very happy at how well they were doing until last week. One set was from seed and the other was a set of seedlings from the garden centre. They were all in the greenhouse with fresh compost and food but all of the baby seedlings have now died and the stronger looking garden centre ones now also look afflicted by something.

The first sign is of the plant wilting from its top leaves downwards. As the wilting becomes worse the leaves are turning yellow.

Anybody have any ideas how to help them please?

 

Blimey,

Could be a few things, might have got too hot on that rare sunny day the other day.

Might be root aphid.

 

I think you`ve overfed them. The nutrients in the compost were quite enough, they didn`t need added feed.