Went to the plot for the first time in a couple of weeks today & found that despite all the rain last week, the sun of the last few days had formed a hard crust on some of the beds. Couldn't face hacking at the surface but wanted to add some organic matter. I covered the surface (not very thickly) with a mixture of manure and leafmould. Now I'm worried that it will just sit on the surface & do no good. There were plenty of worms in the mulch- do you think they will help it to get incorporated, or do I have to go back tomorrow and dig it in?