Raised garden beds provide a wide variety of solutions to gardening problems: utilizing unused space, improving drainage, diminishing weeds, retaining soil warmth and improving access to plant culture. Although raised beds are often constructed of wood, a number of other materials can be used to suit your landscape. Consider building raised beds to capture precious sunlight, increase definition of gardening spaces and beautify your yard.
Create raised beds in any area where digging a bed into the ground may be difficult. A raised bed can be constructed over severely rocky soil or close to a house foundation where in-ground beds may contribute to drainage issues. Use a series of raised beds to convert a steep slope into garden beds. Edge a patio or sitting area with raised beds to define space--bench-width edges can even provide extra casual seating.
Use chemical-free lumber or plastic lumber to create raised garden beds. Although leaching of arsenic into soil has been addressed, much outdoor lumber still contains copper and other chemical salts that are of concern in areas where small children play or vegetables are grown.
Cut 2-inch-deep lumber (in widths from 6 to 12 inches) in lengths and widths needed to make a hollow box the size of your bed. Assemble box with screws. (For secure construction, place screws 2 inches apart.) Boxes can be nailed instead, but screws provide sturdier construction.
Use masonery blocks, bricks or large rocks to build raised beds. Bricks will require mortaring for secure construction, but large masonery blocks with hollows or large rocks possess enough weight to edge beds without mortar. Set large masonery blocks on edge so that their hollows can be filled with soil and planted; the extra warmth retained by masonery after direct sun has passed make them ideal for heat-loving herbs and small annuals. Large rocks retain warmth and enable you to build beds with curved or fluid edges.
Line raised beds with permeable landscape fabric or a 1-inch layer of newspapers to give new plants a weed-free start. Both linings will bio-degrade after several seasons, allowing plantings to establish and crowd them out in the future.
Fill your beds with top soil and soil amendments suited to what you wish to grow. Creating these reservoirs of nourishing soil allows you to grow plants that may not do well in regular yard soil. Soil can be mounded slightly in the center, and should come within 2 inches of the height of raised bed walls to create drainage. Avoid filling beds to the top of walls to prevent water-related soil runoff.