I have a bare soil area in my front lawn that I recently amended with several bags of composted manure. I havent gotten the chance to plant anything yet, but I will next month (as soon as the nurseries start discounting their already established perennials that are past their bloom period). In the meantime however, Im concerned about "new" weeds sprouting. I wanted to use some Preen but the back of the package says.....Do not apply Preen Weed Preventer to muck soils or to soils containing more than 10% organic matter. Does anyone know why this is? Should I apply mulch first then Preen (to avoid direct contact with the soil)? Oh, and what is "muck" soil?