Take a look at the benefits of Metal Raised Garden Beds
Many gardeners are currently planning and creating new patio gardens, and raised garden beds are often the best option for professional gardeners who do not have natural garden plots. Garden beds vary greatly in size, material, and cost. The choice of wall framing depends on the availability and cost of construction materials and the desired appearance of the final product in the landscape. Natural preserved wood, such as redwood or cedar, can also be used. If you have an ample supply of native rock on site, it can be mixed together in a dry stack or mortar. Other possibilities include sheet metal, wood, concrete blocks, bricks, or synthetic wood made from recycled plastic. National horticultural publications have raised concerns about the safety of using treated wood as garden beds in food gardens. The U.S. Environmental Protection Agency phased out residential use of wood treated with arsenic-containing compounds in 2003, and these treatments have been modified to use copper-containing compounds. Similar concerns exist with creosote and the use of railroad sleepers for raised garden beds used in food production. After reviewing the available information, we recommend that you use another material: galvanized metal. Galvanized metal raised garden beds will have initial costs and labor, but the finished product will last for many years and provide usable growing space for your plants.
The most convenient width of a raised metal garden bed is 4 feet. This can vary depending on the gardener's goals and terrain. Hillside terraces may require a different garden bed size than a flatland vegetable garden. On hillsides, follow the contours of the land and adjust the depth of the bed to the slope of the hill. On flat ground, you can be more creative. Depending on your goals and needs, make sure the path is wide enough to allow access for equipment and wheelchairs. The center of the garden bed can be accessed from both sides. If you can only access the garden bed from one side, limit the width to 3 feet. Most gardeners find it uncomfortable to tend a garden bed beyond 3 feet. The height of garden beds can vary, but 18 to 24 inches is fairly common. The length of a raised garden bed is not important; 24 feet is probably a good maximum length. A three-foot wide walkway is usually sufficient. These can be covered with a weed barrier or wood chips to reduce weeds.
After building a raised metal garden bed, you will be faced with finding the right soil to fill it. Because raised metal garden beds are raised from the ground, it is important to use an absorbent soil mixture to help retain moisture and nutrients. The ideal soil type is a sandy loam, which is essentially loose, well-drained and rich in organic matter. You can purchase special bagged garden bed soil to fill your metal raised garden beds, or you can experiment by mixing garden soil with potting soil, making sure to use more garden soil than potting mix, usually at a ratio of 5:1. Compost is the ideal soil amendment because it enriches the soil with essential nutrients without leaching chemicals into the soil. You should regularly apply organic compost or mulch to your garden beds to improve the quality of the soil.
Remember to build enough garden beds to allow for crop rotation. Crops from certain plant families need to be rotated with crops from other families to avoid disease and other pests. It can be a challenge to fill a small metal raised garden bed with tomatoes and peppers each year without eventually experiencing disease problems.