Choosing the Right Material for Raised Beds
Raised beds can be built from many different materials, ranging from inexpensive and practical to decorative and more expensive. The best choice depends on the garden’s appearance, budget, durability and how permanent the bed needs to be.
Wood is one of the most common and economical choices. Treated landscape timbers or other treated lumber can provide many years of service, often 10 to 12 years or more. Wood also has an advantage in hot weather because it does not transfer as much heat into the soil as metal does. That can help protect plant roots along the edges of the bed during periods of extreme summer heat. Wood can be cut to almost any length, making it easy to create beds to fit a particular space. The primary disadvantages are weight and the difficulty of moving a wooden bed once it has been assembled.
Metal is another increasingly popular option. Galvanized metal beds, including those that resemble livestock watering troughs, are durable and can last for many years. Decorative metal beds are also available in a variety of shapes and colors and can provide a more finished appearance in a home landscape. Metal is lighter than many other materials, making it easier to move when the bed is empty. The major concern is heat. Metal can become extremely hot in direct sunlight, causing the soil along the inside edges to heat up significantly and potentially damage plant roots. During very hot weather, covering the outside of the bed with a light-colored material such as white plastic or frost cloth can reflect sunlight and help reduce soil temperatures. Light-colored or lightly painted metal is particularly useful in hot climates.
Concrete block offers an inexpensive, durable and flexible alternative. Standard concrete blocks can be stacked to create beds of different shapes and heights, and the blocks can be rearranged if the design needs change. They are also available in lighter-weight versions that are easier to handle. When building a tall bed, however, the weight of wet soil can push the blocks outward. Short pieces of rebar driven through the holes in the blocks and into the ground can help keep the walls in place. Concrete is especially flexible, allowing you to create custom shapes. Beds can also be built in tiers, with shorter sections in front and taller sections in back. This works particularly well for flower gardens because plants with shallow and deep root systems can be placed at different levels.
Recycled and repurposed materials can also be used to create small raised beds. Old tires, for example, can be stacked and filled with soil to create inexpensive planting spaces. Wheelbarrows and other large containers can serve a similar purpose. These options can be useful when cost or available materials are the primary considerations, although their appearance may not suit every landscape.
Whatever material is chosen, the size of the bed is important. A bed should be narrow enough so that the soil and plants can be reached without stepping into it. A width of about 4 feet tends to work well because plants can be reached from either side. The amount of soil also needs to match the plants being grown. Large plants such as tomatoes require substantially more root space than small ornamental plants, so very small containers can limit their growth.
Raised-bed materials can therefore serve different purposes. Wood provides an economical, traditional option with good heat insulation; metal offers durability and a contemporary appearance but requires attention to heat; concrete blocks provide inexpensive, flexible construction; and repurposed containers offer a low-cost way to create smaller growing spaces. Choosing the material that fits the location and the intended use can make a raised bed both functional and attractive.
Related Videos:
How to Mix Soil for a Raised Bed: A Simple Guide to the Right Ingredients
Choosing the Right Soil for a Raised Bed Garden
Building Raised Bed
Replacing a Wooden Raised Bed with Concrete Block
A Season-Long Look at Five Mulches: What Worked, What Didn’t
Related Resources:
Soil Health in Raised Beds
Raised bed gardens
Wood is one of the most common and economical choices. Treated landscape timbers or other treated lumber can provide many years of service, often 10 to 12 years or more. Wood also has an advantage in hot weather because it does not transfer as much heat into the soil as metal does. That can help protect plant roots along the edges of the bed during periods of extreme summer heat. Wood can be cut to almost any length, making it easy to create beds to fit a particular space. The primary disadvantages are weight and the difficulty of moving a wooden bed once it has been assembled.
Metal is another increasingly popular option. Galvanized metal beds, including those that resemble livestock watering troughs, are durable and can last for many years. Decorative metal beds are also available in a variety of shapes and colors and can provide a more finished appearance in a home landscape. Metal is lighter than many other materials, making it easier to move when the bed is empty. The major concern is heat. Metal can become extremely hot in direct sunlight, causing the soil along the inside edges to heat up significantly and potentially damage plant roots. During very hot weather, covering the outside of the bed with a light-colored material such as white plastic or frost cloth can reflect sunlight and help reduce soil temperatures. Light-colored or lightly painted metal is particularly useful in hot climates.
Concrete block offers an inexpensive, durable and flexible alternative. Standard concrete blocks can be stacked to create beds of different shapes and heights, and the blocks can be rearranged if the design needs change. They are also available in lighter-weight versions that are easier to handle. When building a tall bed, however, the weight of wet soil can push the blocks outward. Short pieces of rebar driven through the holes in the blocks and into the ground can help keep the walls in place. Concrete is especially flexible, allowing you to create custom shapes. Beds can also be built in tiers, with shorter sections in front and taller sections in back. This works particularly well for flower gardens because plants with shallow and deep root systems can be placed at different levels.
Recycled and repurposed materials can also be used to create small raised beds. Old tires, for example, can be stacked and filled with soil to create inexpensive planting spaces. Wheelbarrows and other large containers can serve a similar purpose. These options can be useful when cost or available materials are the primary considerations, although their appearance may not suit every landscape.
Whatever material is chosen, the size of the bed is important. A bed should be narrow enough so that the soil and plants can be reached without stepping into it. A width of about 4 feet tends to work well because plants can be reached from either side. The amount of soil also needs to match the plants being grown. Large plants such as tomatoes require substantially more root space than small ornamental plants, so very small containers can limit their growth.
Raised-bed materials can therefore serve different purposes. Wood provides an economical, traditional option with good heat insulation; metal offers durability and a contemporary appearance but requires attention to heat; concrete blocks provide inexpensive, flexible construction; and repurposed containers offer a low-cost way to create smaller growing spaces. Choosing the material that fits the location and the intended use can make a raised bed both functional and attractive.
Related Videos:
How to Mix Soil for a Raised Bed: A Simple Guide to the Right Ingredients
Choosing the Right Soil for a Raised Bed Garden
Building Raised Bed
Replacing a Wooden Raised Bed with Concrete Block
A Season-Long Look at Five Mulches: What Worked, What Didn’t
Related Resources:
Soil Health in Raised Beds
Raised bed gardens