Posted: 22/08/2015 at 12:31
Normally you'd feed the ground before laying turf or sowing seed. You'd then delay any further feed for a good 6 months or so as the seed/turf is establishing and getting roots down etc. I doubt the leaves will have anything to do with the issues Vegemight. It may be that you haven't fed enough prior to laying, but that's something you can rectify when you start grass maintenance in spring.
You could apply a liquid seaweed feed just now, or something similar. Do that before you do any new sowing of seed. It's common for any grass to look a bit tired at this time of year - long spells of hot weather create browning, whereas up here, we've had so much rain that any nutrition gets washed out so the grass can look a bit yellow. I don't worry too much about it. I only feed in spring (a weed and feed product) and then mow very regularly - not too short. That keeps it looking decent.
PS Dove was right when she said scatter a bit of grass seed over the whole area so that you don't get two different shades - which doesn't look good!