Build a Raised Cedar Garden Planter Box
Woodworking

Build a Raised Cedar Garden Planter Box

Build a sturdy 4x4 foot raised garden bed perfect for vegetables, herbs, or flowers. This beginner-friendly woodworking project takes about 2-3 hours and requires basic tools. Cedar's natural rot resistance makes it ideal for outdoor garden use.

AM
Alex M.· Jul 9, 2026
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Gather materials and plan your workspace

Collect all your cedar boards, hardware, and tools. Choose a flat outdoor workspace with good ventilation for cutting and assembling. Lay out a drop cloth or work on grass to protect surfaces.

cedar boardsmeasuring tapepencilwork glovessafety glasses

Measure and mark your cedar boards

Using your measuring tape and pencil, mark the four 8-foot cedar boards into eight 4-foot lengths (four for long sides, four for short sides). Double-check each measurement before cutting. Mark clearly on the face of each board.

measuring tapepencil8-foot cedar boards

Cut the cedar boards to length

Using your circular saw or hand saw, carefully cut along your marked lines to create eight 4-foot pieces. Wear safety glasses and work gloves. Keep cuts straight and perpendicular to the board edges for clean corners later.

circular sawsafety glasseswork gloves

Sand rough edges

Use 80-grit sandpaper to smooth any rough cut edges and splinters on all eight boards. Pay special attention to the cut ends. This prevents splinters during assembly and creates a finished look.

80-grit sandpaperwork gloves

Lay out your first layer frame

Arrange four of your 4-foot boards in a square on the ground. Position them so each board's end sits flush against the face of the adjacent board (forming butt joints at corners). This creates your bottom layer.

4-foot cedar boards

Pre-drill corner holes for first layer

At each corner, use your drill and 1/8-inch bit to pre-drill two pilot holes through the face of one board into the end of the adjacent board. Space holes about 1 inch from top and bottom edges, centered on the board thickness. This prevents splitting.

power drill1/8-inch drill bitpencil

Attach first layer corners with screws

Drive one 3-inch exterior wood screw through each pre-drilled hole using your drill. Keep corners square by checking with a carpenter's square as you work. Tighten screws firmly but don't over-tighten and strip the wood.

power drill3-inch exterior wood screwscarpenter's square

Add reinforcement brackets to first layer

For extra corner strength, attach one metal corner bracket on the inside of each corner using 1-inch screws. Position brackets flush with the top edge of the boards. This step is optional but recommended for durability.

metal corner brackets1-inch screwspower drill

Stack and align second layer boards

Place your remaining four boards on top of the first layer, offsetting the corner joints so each new board spans across the joint below (like bricks). This creates a stronger interlocking structure. Check alignment carefully.

4-foot cedar boardscarpenter's square

Pre-drill and attach second layer corners

Repeat the pre-drilling process for the second layer corners, then drive 3-inch screws through the pilot holes. Additionally, drive screws down through the second layer into the first layer at each corner for vertical stability (two screws per corner, angled slightly).

power drill1/8-inch drill bit3-inch exterior wood screws

Secure layers together along sides

Along the middle of each 4-foot side, drill pilot holes and drive 3-inch screws down through the top layer into the bottom layer. Space these every 18-24 inches. This prevents boards from bowing outward under soil pressure.

power drill3-inch exterior wood screwsmeasuring tape

Position planter in final location

Carefully move your assembled planter to its permanent garden location before filling. Choose a spot with appropriate sunlight for your plants. Ensure the ground is level, or level the ground where the planter will sit.

carpenter's levelwork gloves

Add landscape fabric (optional)

If desired, line the bottom of your planter with landscape fabric to prevent weeds growing up from below while allowing drainage. Cut fabric to size, drape it inside, and staple to the inner walls about 2 inches below the top edge.

landscape fabricstaple gunscissors

Fill with soil and plant

Fill your planter with quality garden soil or a mix of soil, compost, and peat moss. Fill to about 2 inches below the top rim. Water thoroughly, let settle overnight, then add plants, seeds, or seedlings according to your garden plan.

garden soilgarden trowelwatering can