Sheet composting is good for certain things, but I don't like the idea of spreading millions of weed seeds with sheet composting in a flower bed. I like the idea of killing as many seeds first, then applying the compost. Maybe trench composting would work well in some circumstances in which the soil would never be turned deep enough to undercover all the weed seeds that were buried. A nice clean composted bed can be ruined in a hurry with careless sheet composting of seedy weedy plant debris.
