Raised Beds

What are Raised Beds?

Raised gardening beds are constructed "containers" which hold the soil and plants higher than the level of the ground. They can be as low as 4 to 6 inches to separate the area from a lawn, or higher so older gardeners can sit down while they garden and people in wheelchairs can easily reach their plants.

Why have Raised Beds?

There are several good reasons to build raised gardening or planting beds as part of a greening project.

Building Raised Beds

Size and shape: A raised bed can be any shape, but typically they are rectangular or square because they are constructed with lengths of wood. When designing or building a raised bed it is important to remember that gardeners will probably need to reach the center of the bed from the edge. Therefore, it is recommended that you keep the width of the beds narrower than four feet wide for gardens. They can be as long as you like. If the bed holds another type of planting, such as trees and shrubs, they can be wider. The higher the bed the more expensive it will be to construct and fill with soil.

Hint: If your bed is deeper than 18 inches, use stone, sand, gravel, or another clean fill as the bottom layer and save on topsoil costs.

Materials: Wood is a good, relatively inexpensive material to choose. Keep in mind that wood eventually rots when it sits in contact with water; therefore you should consider approved types of pressure treated wood. CCA 40-year wood has been approved by the FDA for use in contact with garden soil. (CCA stands for copper chloride arsenic and the wood is rated to last outdoors for at least 40 years.) If you wish to take further precautions against the chemicals in the wood you can line the inside of the bed with plastic before you fill it with soil. Do not use old wood that has been painted with lead paint, used rail road ties, or unapproved pressure-treated wood. These may add contaminants to the soil. Stone, brick, cobblestone, or other masonry is also suitable for low beds. It is more difficult to construct taller beds with these materials. Poured concrete is quite an investment and is not as asthetically pleasing, but will last a long time. Do not use asphalt as an edge for a bed. It contains petroleum products that may contaminate soil.