Corrugated metal raised beds are becoming increasingly popular for their durability and long-lasting designs. They look great and keep your garden elevated, but they’re not without fault. If you’re thinking about getting a metal raised bed, it’s important to know how long it’ll last and when you’ll need to replace it.
Corrugated metal raised beds last for up to 60 years. Most of these beds last at least 30 years, making them much more long-lasting than wooden raised beds. Adding cedar supports in all four corners can make the bed more durable. It’s also important to have support beams outside of the metal.
In this article, we’ll talk about how long a corrugated metal raised bed should last, how you can make yours last longer, and whether or not they’re resistant to pressure, UV rays, water, etc.
How Many Years Will Corrugated Metal Raised Beds Last?
It’s estimated that corrugated metal beds should last between three to six decades (source) A realistic timeline is probably closer to 20 years before some level of degradation begins. Proper structural supports are essential to get the most out of these planters.
Not only do they protect against unexpected soil shifting, but they also prevent damage from earthquakes, strong winds, and other natural disasters.
Keep in mind that you can build a corrugated metal raised bed at home or purchase a pre-built model. If you build a DIY bed, we suggest adding internal structural supports. Connect four sheets of corrugated metal in a rectangle, then drill the blocks in each corner.
You can place the bed over bare soil, then fill the bed with compost and topsoil.
The Sunnydaze Raised Metal Garden Bed (link to Amazon) is an excellent example of a simple 24” x 11.75” corrugated bed. It comes in multiple colors and only weighs seven pounds, which means it’s easy to move around the yard.
Pro Tip: If you really want to crank up the quality have a look at the vast options available from Vegega. They offer free shipping and have the largest selection I’ve seen online.
It also comes with all of the hardware needed and a one-year manufacturer warranty.
How to Make Corrugated Metal Beds Last Longer
To make corrugated metal beds last longer, follow these steps:
- Balance the soil’s pH as often as possible. Mike’s Backyard Garden explains acidic soil can corrode corrugated metal (source) If the metal is exposed to extremely low-pH soils and plants, it won’t last too long. Add neutral soil and garden water to maintain a healthy soil pH if it gets too low.
- Keep the soil more hydrated than usual. Corrugated metal beds attract heat. The reflective metal absorbs some of the heat and transfers it into the soil. This means your garden can dry out a bit quicker than a wooden garden bed. All you have to do is use Wyndham House Watering Globes (link to Amazon) to fix this issue.
- Use wooden supports inside the bed and support beams outside of the bed. Place a 4” x 4” corner block in all four corners before laying the soil. These wooden blocks prevent the metal from caving in under the pressure of the heavy dirt. You can place corner blocks at the inner top portion for additional support.
- Avoid plastic liners if possible. Plastic liners prevent weeds from coming through the metal bed, but they also cause rust. If your metal bed rusts from poor drainage through the plastic layer, it’ll fall apart within a few years. Instead, consider landscape fabric or aerate the soil beforehand.
- Clean the bed every few weeks. Spray and dry the outside of the corrugated metal bed to get rid of rust spots, dirt, and grime. If you prevent these issues from getting out of hand, they won’t deteriorate the metal. Furthermore, cleaning the bed keeps spiders and other bugs out of the raised garden.
Garden beds are designed to handle the heat, moisture, and wind from local weather conditions. However, you can add several years to your corrugated metal bed’s lifespan with the tips mentioned above. Not only will these suggestions prevent rust and corrosion, but they’ll also stop the bed from caving in on itself.
Are Corrugated Raised Metal Beds Resilient?
Corrugated metal raised beds are resilient against heat, excessive weight distribution, and pressure. The metal is quite flexible and sturdy, which means it doesn’t crack as easily as plastic. Furthermore, corrugated metal is made to withstand direct pressure, including that of countless pounds of soil and plants.
Here’s why corrugated metal raised beds can last longer than most garden beds:
- They don’t experience wood rot. Wood-based raised garden beds can get termites, wood rot, and other problems. However, corrugated metal is resilient and doesn’t experience a fraction of the same issues as wood. Furthermore, it wicks moisture away rather than soaking it in and expanding or breaking apart.
- These beds are quite flexible without permanently bending. The soil in a raised bed can weigh hundreds of pounds. This amount of weight can break weak metals apart, but corrugated metal moves with the shifting soil. The rippled design provides natural structural support for many years to come.
- They won’t splinter or crack from uneven weight distribution. If you use a lot of rocks in the bed or the soil unexpectedly shifts in one direction, you won’t have to worry about your corrugated metal bed breaking apart or splintering. Wood shatters, but corrugated metal is durable and resistant.
- Corrugated metal beds can limit bacterial growth. Zinc is found in most corrugated metals, and it naturally kills a lot of bacteria. Furthermore, the metal can’t absorb moisture, unlike wooden beds. Zinc’s antibacterial properties stop bacteria from spreading throughout the edges of the soil.
- They can withstand quite a bit of heat. These beds reflect a lot of the sun’s UV rays. The absorbed heat is transferred into the soil, which prevents the metal from cracking or breaking from the temperature increase. Furthermore, metal has a much higher temperature resistance than most other garden bed materials.
There’s no doubt that corrugated metal beds can last for several decades. Cleaning and maintaining the beds will increase their longevity, too. These beds take a little bit longer to create and place, but most gardeners find that they’re more than worth the time and effort.