How to Build Raised Garden Beds With Corrugated Metal

There's nothing better than walking outside and picking the sweet fruits and vegetables from your own garden in your own yard. With this corrugated metal raised garden bed, you get the best of both worlds — the wonderful garden function and a beautiful addition to your yard. What could be better?

Image Credit: Photograph by Shayna Orrino

Things You'll Need

  • 2 x 6 x 10' cedar boards

  • 2 x 6 x 8' cedar boards

  • 4 x 4" x 10' cedar post

  • Tape measure

  • Table saw

  • Sliding compound miter saw

  • Drill with twist bits and screwdriver bit

  • Pencil

  • Framing square or speed square

  • Hammer

  • Chisel

  • Corrugated metal, new or old

  • Grinder or circular saw with metal-cutting blade

  • 3 1/2 inch deck screws

  • 1 1/2 inch self-tapping screws

  • Landscaping fabric

  • Scissors

  • Soil

Tip

Sponsored tip: Need tools for your project? Check out RentalHQ and get connected with local businesses that’ll help you rent the equipment and tools you need.

Step 1: Determine Box Size

Depending on the size of the area you have available, choose an overall length and width for your garden box. Ours is 4-feet wide x 8-feet long x 21-inches tall. The size of your box will determine how much lumber you need. Cedar is great wood choice for outdoor projects, since it is naturally resistant to rot and insect damage.

Tip

Don't make your garden box too wide, or you won't be able to reach the middle of the box from either side.

Step 2: Build the Bottom Frame

To start, begin building the frame of the garden box. Because we purchased 2 x 6 boards, we had to rip down the bottom board of the box in half lengthwise, using a table saw.

Image Credit: Photograph by Shayna Orrino

With the wood ripped down, cut two side boards 8 feet in length and two end boards at 4 feet in length, mitering the ends at 45 degrees, using a miter saw. Lay out the pieces to create a rectangle shape, as shown here.

Image Credit: Photograph by Shayna Orrino

Drill pilot holes at the corner joints, using a 1/8-inch twist bit. The pilot holes will prevent the wood from splitting when you drive screws.

Image Credit: Photograph by Shayna Orrino

Then use two 3 1/2 inch deck screws to secure each corner.

Image Credit: Photograph by Shayna Orrino

Follow the same pattern on all four corners to create a sturdy bottom frame.

Step 3: Cut & Notch the Corner Posts

Now you will create the four corner posts for your raised bed. For a cleaner look and sturdy construction, we opted for a design that will mortise the top and bottom frame into notches cut into the 4 x 4 posts. Begin by cutting four corner posts from the 4 x 4s at 18 1/2 inches in length.

Image Credit: Photograph by Shayna Orrino

Now, cut the notches where the 2 x 6 top rails will fit into the posts. Use a 2 x 6 board as a template to outline the notch on the post. Remember that a 2 x 6 board is actually somewhat smaller than those nominal dimensions — 1 1/2 inches x 5 1/2 inches, which will be the size of your notches.

Image Credit: Photograph by Shayna Orrino

With the rail outline drawn on the post, use a miter saw to make the necessary cuts, down to the depth of the outlines. The saw won't go all the way through the block, but it will cut deep enough along the outline to allow you to knock out the corner and finish the notches with a hammer and chisel.

Image Credit: Photograph by Shayna Orrino

With the corner piece cut, pull out the separated wood.

Image Credit: Photograph by Shayna Orrino

This is what it will look like:

Image Credit: Photograph by Shayna Orrino

For a clean, smooth square corner, use a hammer and sharp chisel to cut out the remaining wood and square off the notches. The notch needs to be perfectly smooth and square to allow the top rails to fit.

Image Credit: Photograph by Shayna Orrino

Next, cut the notches for the lower bottom rails. These are made from smaller lumber pieces, so they will require smaller notches. Use the bottom frame pieces as guides to mark your notches at the bottom of the posts, then cut and finish the notches in the same manner you used for the top notches.

Image Credit: Photograph by Shayna Orrino

Again, use the saw to score the wood along the outline.

Image Credit: Photograph by Shayna Orrino

Use the hammer and chisel to remove the corner and square off the notches. When both sides are notched, you'll be left with this:

Image Credit: Photograph by Shayna Orrino

Tip

Use the first corner post as a guide to mark the rest of our posts. The marking process will go much faster this way.

Image Credit: Photograph by Shayna Orrino

Step 4: Add the Corner Posts to the Bottom Frame

With the corner posts cut and notched, begin attaching them to the bottom frame.

Image Credit: Photograph by Shayna Orrino

Position the first post upright on one corner of the bottom frame so the notches fit tightly over the frame. Use a square to make sure each corner is straight and square to the frame.

Image Credit: Photograph by Shayna Orrino

Drill pilot holes, and use the 3 1/2 inch screws to attach the posts to the the bottom frame.

Image Credit: Photograph by Shayna Orrino

Follow the same pattern until all four sides are attached.

Image Credit: Photograph by Shayna Orrino

Next, add the side rails. Cut the two 2 x 6 boards to 8 foot lengths, and two to 4 foot lengths, bevel-cutting the ends at 45 degrees (this can done on your table saw or with a sliding compound miter saw). Position the 8 foot-long side boards into the post notches. Drill pilot holes and secure the posts to the rails with 3 1/2 inch screws.

Image Credit: Photograph by Shayna Orrino
Image Credit: Photograph by Shayna Orrino

Position the 4-foot end rails into the notches, then drill pilot holes and secure them to the posts with screws.

Image Credit: Photograph by Shayna Orrino

Add the side bracing on the long sides, which will make the frame a little more sturdy. Cut two 2 x 6 boards to 10-inches long. Position them on the long sides, midway between the corner posts. Secure them on the top and bottom frame members with 3 1/2 inch screws driven diagonally (known as "toe-nailing") through the side braces and into the top and bottom frame members.

Image Credit: Photograph by Shayna Orrino

Step 5: Add the Corrugated Metal

With the frame built, it's time to add the corrugated metal panels to each side. Measure and mark the metal panel for long strips 18 1/2 inches wide.

Image Credit: Photograph by Shayna Orrino

Using a grinder or circular saw with a metal-cutting blade, cut the metal strip along the marked line.

Image Credit: Photograph by Shayna Orrino

Next, cut the strips to the proper length; in our case, this means two 4-foot lengths for the ends of the planter, and two 8-foot lengths for the long sides.

Image Credit: Photograph by Shayna Orrino
Image Credit: Photograph by Shayna Orrino

Insert the cut metal pieces into the frame on the inside of the planter. Use care, as the cut metal edges may be sharp.

Image Credit: Photograph by Shayna Orrino

Now, use the self-tapping screws to attach the metal to the wood frame. Drilling small pilot holes can make this easier.

Image Credit: Photograph by Shayna Orrino
Image Credit: Photograph by Shayna Orrino

Make sure to drive plenty of screws into the top and bottom frame and into the side braces to provide plenty of support.

Image Credit: Photograph by Shayna Orrino

Step 6: Add the Corner Blocks

Because the metal doesn't perfectly line up straight on each corner, it may leave the edges with a slight gap. Use a piece of cedar, ripped down to 1 1/2 inches x 2 inches to reinforce the ends of the panels. Screw small boards on both sides of each corner — a total of eight strips.

Image Credit: Photograph by Shayna Orrino

Tip

While this step certainly makes the box look more finished, it's not essential to the overall build. If your metal creates a nice corner edge, feel free to skip this step.

Step 7: Fill with Dirt

Now, you can move the planter into its final position and begin filling the box with dirt. Because the old corrugated metal we used had a few minor holes and rust spots, we used landscaping fabric to line those areas:

We simply cut the fabric to size...

Image Credit: Photograph by Shayna Orrino

Placed it in the box, and pushed the dirt up against the fabric...

Image Credit: Photograph by Shayna Orrino

And continued filling the boxes to the desired height.

Tip

You can use any soil or dirt you like, but for best growing, it's recommended to use a packaged container soil mixture, or a mixture of top-soil and organic material, such as peat moss or compost.

Image Credit: Photograph by Shayna Orrino

Step 8: Add the Top Cap

This step could easily be done before adding the dirt, but we decided to add the cap last. Not only does it nicely frame out the top of the box, but it also adds a nice ledge.

For the cap, we used 2 x 6 cedar boards, 10-feet long. We wanted the cap to hang over the actual frame of the box, so we added an extra 2 inches to the frame, cutting each corner piece at a 45-degree miter.

Image Credit: Photograph by Shayna Orrino

Drill pilot holes, then drive screws to secure the top cap to the frame.

Image Credit: Photograph by Shayna Orrino

We used several screws on the top, the sides, and the corners to firmly secure the cap.

Image Credit: Photograph by Shayna Orrino
Image Credit: Photograph by Shayna Orrino

Once all of the boards were installed and screwed in place, we were left with this:

Image Credit: Photograph by Shayna Orrino

Step 9: Add Plants & Enjoy!

The final step is adding your plants and seeds!

Image Credit: Photograph by Shayna Orrino

Tip

Don't forget to add any soil amendments to if necessary!

Enjoy your new garden box!

Image Credit: Photograph by Shayna Orrino
Image Credit: Photograph by Shayna Orrino

Not only is it a practical addition, but it's also beautiful.

Image Credit: Photograph by Shayna Orrino

For maximum impact, build more than one to give a nice, cohesive look to your yard.

Image Credit: Photograph by Shayna Orrino

Enjoy, enjoy! And don't forget, this project can easily be customized to fit your space requirements and your garden type! Happy gardening!