How you make your raised garden bed determines whether it requires a liner. Beds created over a cultivated area where plant roots are allowed to penetrate existing soil do not require a liner. Those placed on top of the existing soil, usually because the soil is unsuitable for growing, and filled with a soil mixture that serves as the sole bed for the plants require a liner, or barrier, between the existing soil and the soil mixture in the raised bed to prevent weeds and invasive plants from growing into the raised bed.
Place the raised bed in the preferred location. Vegetables and most flowers prefer full sun. Select an area that receives 6 to 8 hours of direct sun a day.
Measure the inside dimension of the bed and add 8 inches to both the width and length. Cut the landscape fabric to this size, or collect enough newspaper to fill the area.
Line the bottom of the raised bed with several layers of recycled newspapers or landscape fabric. Fit the material snugly against the inside walls of the bed and fold the excess material upward on the inside walls to create a tight barrier to weeds.
Fill the bed with soil mixture, firming it down along the sides and in the corners to secure the liner in place.
