How to Build Window Planter Boxes


Create curb appeal for the front of a home by building window planter boxes to hang under street view windows. Choose cedar wood or paint the box to match or coordinate with the home's exterior color. Place a plastic liner inside the window box to extend its life and reduce maintenance. Adjust the dimensions to create planter boxes for various-sized windows throughout the home. Use the same instructions to build railing boxes for a porch or patio.

Step 1

Measure the length of the window the box will hang under. A 36-inch window box is a standard size.

Step 2

Measure and cut two 36-inch by 6-inch sections for the front and back pieces of the box. Measure and cut one 36-inch by 8-inch section for the bottom of the box. Measure and cut two 6-by-6-inch sections for the sides.

Step 3

Drill a 1-inch diameter hole into the bottom center of the box for drainage. Drill holes in the four corners of the front, back and bottom sections to make it easier to screw the sections together.

Step 4

Sand all sections to smooth rough edges before assembling the box. Glue the front and back sections to the side sections with wood glue. Screw 1-1/3 inch screws through the pre-drilled holes to hold the shell of the box together.

Step 5

Glue the bottom section to the shell with wood glue. Screw 1-1/3 inch screws through the pre-drilled holes in the bottom section to hold it in place on the window box.

Step 6

Paint or stain the pieces if you like, followed by an application of polyurethane sealer for added protection.

Step 7

Attach a hangar to the window box by drilling a 1/2-inch diameter hole through the box in each of the top corners 1-1/2 inches from the top and sides. A standard 36-inch long box requires two hangars--one installed in each top corner.

Step 8

Mark the house where the hangar bolts will go--the same distance apart as the hangars on the box. Drill a 1/2-inch hole through the mark, and install a hanger bolt so two inches protrudes from the house.

Step 9

Slide the window box onto the bolts protruding from the house. Secure the box by sliding a washer onto each hanger bolt and screwing each nut tight.

Things You'll Need

  • Measuring tape
  • 2 wooden boards, 1-by-8, 6 feet long
  • Saw
  • Sandpaper
  • Paint or stain
  • Paintbrush
  • Drill and drill bits
  • Wood glue
  • 12 screws, 1-1/3 inches
  • Hanger bolts


  • Home Tips: How to Build a Cedar Window Box
  • Western Red Cedar Lumbar Association: Planter Window Box
Keywords: build window box, make window box, homemade window box

About this Author

Jennifer Loucks has over 10 years of experience as a former technical writer for a software development company in Wisconsin. Her writing experience includes creating software documentation and help documents for clients and staff along with training curriculum. Loucks holds a Bachelor of Science major from the University of Wisconsin - River Falls specializing in animal science and business.