[little_kev]

Hi, my 'new growth' is notably yellow, and i'm not sure why. it is apparent on anything with notably voluminous (?) foliage. It's about 5C at night so they all go in nightly, to maybe 18C, dark room. But not sure if it's nutrition, growing in the dark, cold in the day, or my yellow fingered touch.
It's happening with tomatoes, peppers, zuchinni, and even my innocent borage.

Any help and advice appreciated.
Photo attached, and one of a snake in my roses as a ta-v.much-for-looking bonus. 

[mumofstig]

is it still relatively cold in the day, as well then? I'd have put my money on that 

[little_kev]

the temperature's been wandering around; 9-18C in the day.

[Mark's Sussex Allotment]

Is the compost new?

But I cant imagine it would of exhaused the goodness of the compost already .....

[little_kev]

Re: the compost, they started in a veg-specific (new) soil with a smidgen of vermilite on the top/rim, and potted on to universal compost with a little bit of organic fertiliser pellet mixed in.

[Yorkie]

Sounds as though you've got the fertiliser sorted.

Probably is temperatures, but if they don't perk up then you might consider a dilute general purpose feed or something like epsom salts if you can get them.

[snow white]

I also put some fertilser in the potting on compost "to speed things along" but it nearly killed everything.  I rescued them by potting them on again in the same compost but without the extra "goodness".  I think it was too much for them.  They are just now  recovering.  They didn't go yellow though, just wilted and some died.  Lost about half of them.