This growing technique, centuries old, remains popular and useful to the home gardener to get maximum crop yields from input.
Any structure that contains a growing medium above the ground is often referred to as a raised bed. There are several good reasons for raised bed gardening.
A raised bed is ready to plant several weeks before a regular garden plot, especially during a cool, wet spring. The soil of a raised bed warms up faster. Also, excess soil moisture drains away from the bed. Overwatering is less of a problem. The growing medium may be improved or replaced easier. Soil compaction can be greatly reduced or eliminated. Watering and fertilization become more economical. Raised bed increases the effective use of your growing space.
The raised bed garden is both convenient and attractive. Raised beds seem to break tasks of gardening into smaller work units. As you bend or kneel, a raised bed is generally 10 inches closer to you. You feel that you are weeding an individual bed instead of the entire garden.
By designing and using the raised bed technique, you can use 60-80% of its area for growing plants. This almost doubles the space used for growing in a garden laid out in rows.
Successive planting all through the growing season makes green foliage and attractive beds come into production at various times of the year.
Design & Construction
A raised bed garden can be simply made by raking the garden soil into a ridge 4 to 8 inches high away from the foot paths. Permanent raised beds make much better use of the advantages of this gardening technique. The widths of beds are 3 to 5 feet. You must be able to reach all areas within the beds. Once you prepare your soil, you donšt want to walk on it again during the growing season. Sometimes, the bed has only a path on the side, allowing use of a fence or trellis on the other side for climbing and vining plants. Length of beds varies. Width of the path is 1 foot at a minimum and usually 2-3 feet because of the use of wheelbarrows and other garden tools. Paths can be grass or other materials. Grass will need mowing. A gravel or bark-mulched path will not need mowing but may need some weeding.
Material commonly used to hold growing medium and form these permanent beds are 2 x 10 or 2 x 12 inch boards. One-inch boards can be used, as well as concrete blocks, stones or bricks.
The new growing beds can be double dug, which takes a lot of work. Double digging will improve both drainage and aeration. Other soil improvements can be the adding of organic materials, rotted manure, and topsoil. Making the soil loose and deep allows intensive planting.
This bed preparation will take more time initially, but it can be done in the fall, as well as spring. If your available garden space is a dense clay soil with poor drainage, a raised bed is a useable alternative when growing shallow-rooted plants.