Dying Conifers, Please help.

Hi

I bought twenty conifers from a reputable garden centre a year ago, I re-potted them shortly after and they went through the last winter just fine, now some of them appear to be dying but I don't know why, from my experience when a conifer starts going brown it's too late and it will die, is there anything I can do to save them please.
For scale purposes, the pots are 7 inches high.

Trish

 

They're not beyond help at this point Weedaway, but they are hungry and thirsty plants that need to be in the ground. Pots are to restricting for them.

 

I want to wait until they get a bit bigger and stronger before I put them in the ground where I want them so that they stand a better chance against vandalism as they are only small at the moment, would they do better in bigger pots with regular feeding and watering.

 

I think bigger pots a slow release fertiliser and a good water. Make sure the compost drains well, whatever type you use, mix in 25 - 50% horicultural grit. Also stand them somewhere out of the worst of the weather for the winter.

 

Pheew! I am not very good at this, I bought some 'All-purpose muti feed'.
After I put it on my conifers I noticed at the bottom of the label it said "quality feed for fruit & vegetables"
Can you recommend a slow-release or a suitable fertiliser please.