Answer: Three to five inches of soil will support turfgrass and some annual flowers, but not perennials, shrubs or trees. If you can't dig down and break up the shale you might want to bring in some topsoil and make mounds or raised beds in which to plant perennials and shrubs. If you order topsoil, order a 3 way mix which is a combination of garden soil, sand and compost. This makes great soil for gardening because it drains well and has some nutrients in it. You can add some extra compost, aged manure, or other organic matter to help build it into rich garden loam. Best wishes with your garden!
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