How to Build Window Boxes


Window planter boxes give the illusion of a cottage home when filled with full blooming flowers. Window boxes are usually made from cedar wood or painted to match the house siding or accent color. Although the boxes are commonly hung under a window, the same box style works well on a patio or porch railing. A basic pattern allows for creating window boxes of various sizes for use throughout the garden.

Step 1

Choose the size of the window box, which should be based on the dimensions of the window it will hang under. A 30- or 36-inch-long box is common.

Step 2

Cut two sections of wood to the desired length for the front and back of the box. For example, cut two 36-inch-long sections that are 6 inches wide. Cut one section of wood that is the same length as the front and back pieces but 2 inches wider, as this piece is the bottom and fits under the edges of the box. For example, cut the board 36 inches long and 8 inches wide. Cut two sections for the sides that will fit with the width and depth chosen for size. For example, cut two pieces of wood that are 6 by 6 inches.

Step 3

Sand the wood pieces, and paint or stain them prior to assembly to save time. Note that oil-based paint does not require sealing. Wood boxes made of cedar do not need to be painted or sealed.

Step 4

Drill holes in each corner of the front, back and bottom pieces prior to assembling the box. In the center of the bottom piece, drill a hole that is approximately 1 inch in diameter for a drainage hole.

Step 5

Temporarily attach the front and back pieces to the side pieces with wood glue. Screw 1 1/3-inch galvanized screws through the predrilled holes to fasten the front and back pieces to the sides. This creates the box shell.

Step 6

Glue the bottom piece to the box shell. Screw the bottom piece to the box section with 1 1/3-inch galvanized screws.

Step 7

Drill a hole with a 1/2-inch diameter on the back of the box for each hanger bolt. The holes should be 1 1/2 inches down from the top and approximately 1/4 inch from the ends of the box. Mark the location of the holes on the house so they will line up. Drill a 1/2-inch hole into the side of the house at each marking. Install the two hanger bolts so at least 2 inches protrude. Hang the box on the bolts. Fasten a washer followed by a nut to each bolt hanger to hold the box in place.

Tips and Warnings

  • Always wear protective glasses when using a saw and drill.

Things You'll Need

  • 1 1-by-6-inch wood board
  • 1 1-by-8-inch wood board
  • Saw
  • Sandpaper
  • Paint or stain
  • Drill
  • Galvanized screws (1 1/3 inches)
  • Wood glue
  • 2 hanger bolts


  • Home Tips: DIY How to Build a Cedar Window Box
  • Handyman Wire: Window Boxes
Keywords: DIY window box, build a planter, building a window box

About this Author

Jennifer Loucks has been writing since 1998. She previously worked as a technical writer for a software development company, creating software documentation, help documents and training curriculum. She now writes hobby-based articles on cooking, gardening, sewing and running. Loucks also trains for full marathons, half-marathons and shorter distance running. She holds a Bachelor of Science in animal science and business from University of Wisconsin-River Falls.