How to Build an Outdoor Planter Box

This step by step woodworking project is about how to build an outdoor planter box. I designed this planter box so you can add unique appeal to your front porch or to your backyard patio. You can fit plastic containers with flowers into this planter box and make your property super colorful. This planter box has a neat design and it is very easy to build, even if you are a beginner when it comes to woodworking.

We recommend you to invest in the best materials you could afford. Therefore, you should buy weather-resistant lumber, such as pine or cedar. Always take accurate measurements before adjusting the size of the components at the proper size. Drill pilot holes trough the components before inserting the wood screws, to prevent the wood from splitting. See all my Premium Plans in the Shop.

Made from this plan

Building a planter box

Building a planter box

Materials

• A – 8 pieces of 1×4 lumber – 24″ long LEGS
• B – 6 pieces of 1×6 lumber – 16″ long, 6 pieces – 16 1/2″ long BOX
• C – 2 pieces of 2×2 lumber – 16″ long, 4 pieces of 1×4 lumber – 15″ long BOTTOM
• D – 4 pieces of 1×4 lumber – 9 1/2″ long, 2 pieces of 1×2 lumber – 13 1/2″ long, 4 pieces – 6″ long TRIMS
• E – 2 pieces of 1×3 lumber – 20″ long, 2 pieces – 21″ long TOP TRIMS

• 4 pieces of 1×4 lumber – 8′
• 3 pieces of 1×6 lumber – 8′
• 1 piece of 2×2 lumber – 4′
• 1 piece of 1×3 lumber – 8′
• 1 piece of 1×2 lumber – 8′
• 1 1/4″ screws, 1 1/2″ finishing nails
• stain, glue

Tools

• Safety gloves, glasses
• Miter saw, jigsaw
• Chalk line, tape measure, spirit level, carpentry pencil
• Drill machinery and drill bits

Tips

• Adjust the size of the project to suit your needs

Time

• One Day

Planter box plans

Building the side of the planter box

The first step of the project is to build the sides for the planter box. As you can easily notice in the diagram, you should attach the 1×6 slats to the 1×4 legs. Align the edges with attention and leave no gaps between them. Drill pilot holes though the slats and insert 1 1/4″ screws. Add waterproof glue to the joints for a professional result.

Building the opposite sides

Build the other two sides for the planter box using the information from the diagram above. Align the edges flush, drill pilot holes and insert 1 1/4″ screws to lock everything together tightly.

Assembling the planter box

Make sure the corners are square and lock them together with screws. Leave no gaps between the components and add glue.

Fitting the cleats

Continue the project by attaching the 2×2 cleats to the sides of the planter box. Align the cleats as you want, drill pilot holes and insert 2″ screws to lock them into place.

Fitting the bottom slats

Fit the support slats to the cleats, making sure you space them evenly. In order to create even gaps between the slats, you need to place a scrap piece of 3/4″ plywood. Drill pilot holes at both ends of the slats and insert 1 1/4″ screws to lock them into place.

Side trims

Fit 1×4 trims to the sides of the planter box. Secure the trims into place with 1 1/2″ brad nails and waterproof glue.

Building the side trims

Build the x-shaped trims from 1×2 lumber. Cut the ends of the trims at 45 degrees, on both sides.

Fitting the planter box trims

Build the top trims for the planter box from 1×3 lumber. Cut both ends of the trims at 45 degrees and lock them into place with finishing nails.

Square Planter Box Plans

This planter box is a nice addition to any backyard. Make sure you adjust the size of the planter box to suit your needs. Fill the holes and the dents with wood putty and let it dry out for a few hours. Smooth the surface with 120-220 grit sandpaper and apply a few coats of paint stain to enhance the look of the project.

How to Build an Outdoor Planter Box

The first step of the project is to cut the slats for the side panels. Mark the cut lines on the 1×6 slats and get the job done with a saw to get nice and clean edges. If you are using a miter saw, it would be a good idea to use a stop block, so you get consistent results.

Next, you need to attach the 1×4 legs to the side panels. Align the edges with attention and clamp them into place so you can drill the pilot holes properly. Use a drill machinery to drill the pilot holes through the legs.

Insert the 1 1/4″ screws through the legs into the side panels. In addition, you should consider adding waterproof glue to the joints for a professional result.

Attach the other leg for the side panels, using the same techniques described above.

Continue the woodworking project by attaching the corner legs to the side panels. After I aligned the edges I locked the legs into place with a clamp, so I can make pilot holes easily.

Next, I inserted the 1 1/4″ screws to lock the corner legs into place easily. I repeated the process for the opposite side of the planter box.

After you have assembled the two sides of the planter box, you have to lock them together by attaching the other two panels. Drill pilot holes at both ends of the pilot holes and insert 1 1/4″ screws to lock everything together tightly.

Turn the planter box upside down and attach the rest of the 1×6 slats. Leave no gaps between the slats and secure them into place with 1 1/4″ screws. Check if the corners are square for a neat result.

Next, attach the 1×3 trims to the top of the planter box. Cut both ends of the trims at 45 degrees and secure them into place with 1 1/2″ brad nails.

This is a great time for staining the planter box, as you have access to all the area and to the tiny corners. Afterwards, install the side trims to the wood planter box.

Start assembling the X-shaped trims to the sides of the planter box. Make the angle cuts and then secure the trims into place with brad nails and glue.

Fit the rest of the components to complete the side trims.

Attach the supports for the bottom slats. Use a spirit level to make sure the supports are perfectly horizontal.

Attach the bottom slats to the supports.

Fill the holes with wood putty and then smooth the surface with 120-220 grit sandpaper. Apply a few generous coats of poly or lacquer to protect the components from the elements.

This project came out really nice and it is an attraction point in my garden. I love the simple design and I hope you will find all the woodworking techniques used in the project manageable. Remember that you can easily adjust the size of the planter box to suit your needs. If you like my project, don’t forget to SHARE it on Facebook and Pinterest. I have lots of outdoor plans, as well. See a list by category Here.

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