Raised garden beds can be just a few feet square, or form tiers that cover most of the yard. A popular decorative theme is to divide the lawn with multiple raised beds to create both a maze and an ordered display of bulbs, annuals and small perennials. Of course, when making raised garden beds, you must frame them to maintain the integrity of the raised soil as well as keep the bed looking tidy. Selecting the framing material is both a practical and aesthetic matter.
Wooden frames are traditional and the easiest to build, though they may not be strong enough to contain the weight of soil if the intended bed is too large. The strongest and most attractive wooden frame is one comprised of varnished, water-treated oak. It's made of 4-inch by 4-inch posts laid horizontally, stacked, and joined with rebar pins anchoring it to the ground. Atop this is a decorative lip which covers the rebar from view and creates a finished appearance. While it is not necessary, one displays a hand-crafted and original look by dovetailing the corners of all joins.
Frames of brick work well in gardens with an English theme and stand up well to both cold and wet. They can also be made to match brick walkways and patios nearby if the same type of brick is used. This gives you the opportunity to actually place a raised garden bed on stone or concrete rather than just on soil.
The soldier course design--in which the bricks are stacked vertically in a grid--is a bad idea, as they cannot withstand the pressure of the soil placed within the bed for more than a year or two at best. By choosing to stagger the bricks in what is called a running bond you strengthen the integrity of the frame.
Stone-faced frames are expensive, but very strong and can be placed almost anywhere. They are comprised of hollow cinder blocks which are mortared to the desired height and size. Cement fills the hollows so that it is a single solid frame. Stone such as travertine, granite, sandstone, or even marble are used as tiles for the facing and top ledges.