Question: What kind of soil preparation will I need to make for my annuals?
Answer: Think about preparing a sort of potting soil. Annual flowers need loose, well-drained, highly organic planting soils, which means you’ll want to include 4 to 5 inches of organic matter. If you’re dealing with a tight clay soil you might also mix in as much as 1 inch of expanded shale, but only in combination with the organic matter. Rototill all of this 4 to 5 inches into the original topsoil. Not only will you have an excellent planting mix, but you also will have automatically prepared a raised flower bed. That will ensure adequate drainage.