Framed raised gardens are a semi-permanent garden structure requiring some effort and expense. Raised gardens can be framed with lumber to raise the soil a few inches about the ground, or boxes from 1 to 3 feet high can be constructed to hold the soil well above ground-level. Boxes can also be built and set up on supports, cement blocks or tables to make the soil easier to work from a wheelchair or from a standing position without bending. Framed garden beds or boxes make it easy to organize a garden into manageable sections. Frames are normally made from 1-by-4-inch or 4-by-4-inch pieces of lumber, cut to size and nailed or screwed together. Alternatively, gardeners can frame raised beds with split logs from a felled tree, landscape rocks or cement blocks.
Construct raised garden beds without framing by mounding soil. Bring in soil and mound it in rows, squares or rectangles, or dig soil from around the garden area and mound it in the planned sections. Leave the mound as it is, or spread mulch, hay or shredded newspaper around the mounded soil to prevent erosion and conserve moisture. Mounded beds can be covered with organic material to feed garden plants, sealed with black landscaping fabric to control weeds or mulched to retain moisture. Mounding soil to create raised beds is less work than creating framed beds, but it is less permanent, which may be desirable for gardeners who like to try different techniques or new plants each season.
Terracing is a permanent form of raised bed that is useful for hillside and sloped gardens. Till the soil and support it in two or more levels with wooden planks, landscape timbers, retaining wall bricks or landscape stones. Terraced levels can be sharply defined on three-sides by framing material or they can be outlined with decorative landscape materials. Terraced gardens are a good solution for otherwise unusable areas in the landscape.