There are a lot of advantages to using raised garden beds instead of having vegetable plants grow directly in the ground. With raised beds plants are higher, making it easier on the gardener's back, seeds can be planted a bit closer, and the soil is less compacted and drains better. Raised garden beds actually produces 1.5 to 2 times more vegetables than traditional gardening. The best thing about raised garden beds is that they are easy to construct and maintain.
Although you can purchase ready-made plastic garden beds that snap together, they don't allow for the size of your particular garden area. Building your own raised beds from lumber will enable you to cut pieces to fit your needs. The most popular shape is rectangular. You will need two end pieces (the same size) and two length pieces (the same size) for each bed.
Organic compounds are available for treating wood. However, you can choose types of wood that is naturally rot-resistant. Port Orford cedar, red cedar, black locust and redwood are all excellent choices. Most pre-treated lumber has a CCA ( chromated copper arsenate) treatment. This is dangerous to use in your vegetable garden as it may leach arsenic into the soil and you'll get it on your hands without realizing it.
Raised garden beds can also be constructed from brick, stone and concrete pavers. It will take a bit longer to complete, but the effect is nicer for public areas, such as front yard landscaping.
To form the wood frame of a raised garden bed you will need eight or more L-brackets, two for each corner. Using screws, attach the L-brackets at each corner on the inside or outside of the frame. Metal stakes work well to keep your frame in place once it's located in its proper place.
An easy soil mixture for raised garden beds is half organic material (compost) and half soil with a small bag of sand for drainage. Figure your needs before heading to the nursery for your soil. It's easiest to measure for cubic feet. Mutliply the length times the width times the height. So, if your bed is 6' x 3' x 1' you will need 18 cubic feet of soil mixture.