How to Build a Window Box Planter

Building a window box planter is easier than you think. With the right tools, it can be made in less than an hour for under $20 in supplies. It's the perfect afternoon project for any time of the year.

Image Credit: mavis butterfield

Things You'll Need

  • (1) 5/8" x 6"x 8' cedar fence panel

  • (1) 1"x 2"x 6' cedar board

  • Tape measure

  • Pencil

  • Power saw

  • Wood glue

  • Hammer

  • 1 1/2" galvanized finish nails

  • (2) L brackets

  • (4) 1" galvanized screws

  • (4) 5/8" galvanized screws

  • 1" spade drill bit

  • Drill

  • Sandpaper

  • Paint or stain (optional)

Step 1: Cut Your Boards

This project is for a 30" window box. If you want to make one that's shorter or longer, simply cut two pieces of wood the same length for the front and back of the the desired box length. Cut two 5/8"x 6"x 30" pieces of wood and set aside. Next, cut two 5 1/2" x 5 1/2" end pieces.

Image Credit: mavis butterfield

Step 2: Apply Wood Glue to End Pieces

Apply wood glue to the ends of the 5 1/2" x 5"1/2 end pieces.

Image Credit: mavis butterfield

Step 3: Attach Sides to End Pieces With Finish Nails

Using finish nails, attach the end pieces to the front and back boards.

Image Credit: mavis butterfield

Step 4: Measure the Inside of Window Box

Measure the inside of your window box to get the exact measurement you need to cut for the bottom of the window box. For a 30" window box you will need a 5/8"x 6" x 27 3/8" piece.

Image Credit: mavis butterfield

Step 5: Insert Bottom of Window Box

Using a hammer, tap the bottom piece of wood into your window box.

Image Credit: mavis butterfield

Step 6: Finish Nails

Pound finish nails every four inches around the bottom of the window box to secure the bottom to the side and end panels.

Image Credit: mavis butterfield

Step 7: Cut Trim Pieces

Once your box is constructed, it's time to cut your trim pieces. Cut (2) 1"x 2" x 6 1/2" and (1) 1"x 2" x 30" pieces for the sides and front of your window box.

Image Credit: mavis butterfield

Step 8: Apply Trim

Apply wood glue to the bottom of the trim pieces. Then, using your finish nails and hammer, attach the sides first and then the front.

Image Credit: mavis butterfield

Step 9: Sand Rough Edges

Using a medium grit sandpaper, sand the window box down a bit so the edges are not rough. Paint or stain the window box (if you want), and let it sit overnight to dry.

Image Credit: mavis butterfield

Step 10: Drill Drainage Holes

Using a drill and a 1" spade drill bit, drill two holes into the bottom of the planter box.

Image Credit: mavis butterfield

Step 11: Mount the Window Box Using L Brackets

Attach the window planter box to your house just below the window using L brackets and 1 1/2" galvanized screws to hold your window box securely in place. Drill 5/8" screws into the bottom of your planter box to hold the L brackets into place.

Image Credit: mavis butterfield

Step 12: Plant With Flowers

Plant with your favorite sun-worshiping or shade-tolerant flowers, as appropriate; then step back and marvel at the amazing window box you just created.

planted window box
Image Credit: mavis butterfield