
Raised beds boost our vegetables above the often-waterlogged ground in the Organic Gardening test garden, which is located alongside a spring-fed stream. Not every gardener deals with a high water table, but there are other good reasons to plant in raised beds:
Last summer, we built five raised beds from a variety of materials, described below. Each of our beds measures about 4 feet by 8 feet; you can adjust the dimensions to suit your needs, keeping in mind that anything wider than 4 feet will be more difficult to maintain. Our beds are filled with a rich mixture of about two parts soil and one part compost.
Wattle
Hammer 2-foot lengths of rebar into the ground around the perimeter of the bed, spacing them about 16 inches apart and leaving 10 inches of the rebar exposed above ground. Cut long, straight lengths of tree or shrub branches, up to 1⁄2 inch in diameter. Weave the sticks or “wattle” through the vertical rebar, basket style; trim the ends at the bed corners as needed. Once the bed sides have reached the top of the rebar, bend 2-foot sticks in half and poke them into the ground over the woven wattle, holding the sticks in place. Pin the sides in this manner every few feet. Line the sides of the bed with burlap to keep soil from sifting through the wattle.

To build a bed 4 feet by 8 feet, you’ll need 18 pieces of rebar 24 inches long; a strip of burlap about 18 inches wide and 24 feet long; and about 100 long, flexible sticks.
Logs
Choose straight logs about a foot in diameter to create the bed edges. Logs of smaller diameter can be stacked, as we did for the bed ends. To avoid having to move massive logs, line up shorter firewood-length sections.

To build a bed 4 feet by 8 feet, you’ll need two 7-foot logs for the sides and two 4-foot logs for the ends.
Concrete Blocks
Place concrete blocks with open ends facing up to outline the raised bed. The openings can be filled with soil and used as planting pockets for small herbs or edible flowers.

To build a bed 4 feet by 8 feet, you’ll need 16 blocks, 8 by 8 by 16 inches each.
Planks & Rebar
This bed can be constructed of leftover lumber of almost any dimension, so long as the wood is untreated. Hold the planks on edge with short lengths of rebar pounded into the ground every 2 or 3 feet.

To build a bed 4 feet by 8 feet, you’ll need two 2-by-12 planks 8 feet long, two 2-by-12 planks 4 feet long, and 12 pieces of rebar 24 inches long.
Sandbags
Using the long, slender bags of sand that are sold as traction sand, outline a bed. Stack the bags two high.

To build a bed 4 feet by 8 feet, you’ll need 20 sandbags.
See a step-by-step guide to building a raised bed from lumber.
Photos by Paterick Montero
Links:
[1] http://www.organicgardening.com/learn-and-grow/raised-bed-gardening
[2] http://www.organicgardening.com/learn-and-grow/how-to-build-a-raised-bed