Raised Bed Gardening

Raised beds are a life-saver for desert gardening. In some areas, a raised bed vegetable garden may be the only way you can grow your favorite veggies. These beds provide better drainage, offer more control over soil type that flat planting beds, warm faster in spring to allow earlier planting,. minimize bending, are ideal for landscapes with poor soil and add verticle interest.

Planning a raised bed

Before choosing building material, measure the area where you plan to build. When plannnig length and width, make sure you’ll be able to reach the center. A width or length of 4 feet is reachable for almost anyone. Shorter garden beds also prevent soil compaction and allow more space in the area for wheelbarrows and other equipment. An added benefit is that timber is usually sold in a 4-foot length, as well. Take into account the sizes of material (of the individual bricks, stones, or timbers) you want to use, so you don't end up needing half a brick to finish a wall. Alternatively, placing a statue or other centerpeice with a wide base in the middle of the bed will nearly eliminate the need to tend the center.

The height of the beds depends on your plans for them. In most cases a single layer of material is enough. If you’re goal is to reduce bending, the walls should be built to a height that’s comfortable for you -- 2 1/2 feet often works well. Most plants require at least 6-12 inches to root properly so if the bed is intended to provide something better than the local clay, sand, or gravel, the bed will require a height of at least ten inches, filled with rich topsoil.

Material
There are many inexpensive materials available to build the sides of a raised bed, primarily wood, stone, concrete, and plastics. If you plan to sit on the sides, go with a sturdy material that can well secured.

Wood
Although any wood will eventually decay, it's a reasonably inexpensive material for the shorter term. If you choose wood, look for a naturally rot-resistant type like redwood, hemlock, cedar, or oak. Pre-formed landscaping logs, such as cherry stone timbers, are another option. A hole can be drilled through each ends, and re-bar inserted through the holes to hold the logs in place. Avoid railroad ties, however, which contain toxic preservatives that will leach into the soil.

Brick and blocks
These provide a classic, finished look, offer more flexibility in choosing the shape and color of the bed walls, and endure well. They can be mortared together or held in place with re-bar.

Stone
Stone raised beds add a rustic touch to the landscape and a simple to build. Either purchased from a landscape rock yard or found free in your own backyard. For lower walls (under two feet) dry stacking the stones, using the dirt of the bed behind them to hold them in place, is enough. For higher walls, stones can be mortared together.

Plastic
For low price and low-maintenance, plastic is the way to go. Plastic building panals and "timbers" come in a wide selection of styles and are nearly impervious to insect damage or rot.

Building the beds

Around the area of the bed, dig an edging ditch about 4 inches deep with a flat shovel and pile the dirt to one side to be used in the bed later. When the ditch is completed, slope the inside of your ditch to about 45 degrees, smoothing out the dirt as you work. Building the sides will depend on which material you've chosen.

Filling the beds

One of the prime advantages of raised garden beds is the chance to work with the best soil available. Fill your raised bed with a good mix of quality potting soil, mulch or compost, sand, vermiculite and a sprinkling of a dry fertilizer. If the soil in your area is healthy, include some of that, as well. Just make be sure that the soil is disease free. As you water, that the soil level will settle, so water thoroughly and let it rest a day or two before planting.