I am going to start doing a lot of top-dressing of lawns and am looking for a good organic mix. What I have used up to this point is a mix my local distributer sells which is 50% topsoil and 50% GroCo ( 90% sawdust and 10% bio solids ) ( I think bio solids is the correct word, its processed sewage ) I talked to a local Organic nursery to have them potentially sell my top-dressing service and his feedback was I need to change my mix to a more organic friendly mix. He said yes bio solids may be considered organic but he would not be comfortable recommending it. Also he said he would like to see pete moss instead of sawdust. That may be an availability problem for me. Thats enough from me you know my problem, What can you suggest.