Use 9 layers of newspaper. No matter what method you used, chemical or non chemical, you are now ready to fill the planting bed with topsoil. Put 8 to 12” of good rich topsoil in the bed. Make sure the soil is higher in the back, closest to the wall, so the water drains away from the building. If you are creating an island planting make the center of the bed the highest point. Make sure the topsoil you buy is well drained and rich in organic matter. Buying topsoil is a tricky game, you’ve got to be careful and shop around. Topsoil is one item that you do not want to order over the phone, sight unseen. This is what you are looking for when buying topsoil: Topsoil that is rich in organic matter will be very dark in color. If the soil is light in color it is probably just fill sand. The other thing you’ve got to watch for is how well drained the soil is. Topsoil that has a clay base is poorly drained and sticky, and your plants will not be happy at all. They might even die if they are too wet. Once a clay based topsoil dries out it gets very hard. Today most topsoil is run through a screener to remove the clumps, rocks, roots, and sticks. There is nothing wrong with buying unscreened topsoil, especially if you’ve visually inspected it and have found it to be of good quality.