[mrs bouquet]

did weed,feed and moss kill on lawn 8 days ago and then watered.  All the
weeds have grown and the moss has gone black.  have not mown it yet.  do you have to scarify it first, if at all.  there's not much grass left ?  Mrs. Bouquet

[Gwiz]

I'd give it a mow (not a scalping) and then scarify later in the season.
you could give it a "bit of a rake" just to get some of the moss out.
After that, ago over with some grass seed and a little top dressing and water again.

[mrs bouquet]

thanks for that Graham, you early bird.  Mrs Bouquet.

[gobs]

did weed,feed and moss kill on lawn 8 days ago and then watered.  

With what? Depending, think twice where you put your cuttings and rakings.

See this