diy window flower box

DIY these darling window flower boxes just in time for spring

(Last Updated On: April 8, 2023)

A window box is a beautiful way to brighten up your outdoor living space. It can instantly add a lot of simple charm and color to your home. Plus, it’s a fairly easy home improvement project – no fancy DIY skills needed!


  • 1×10 and 1×3 cedar
  • 5 lag bolts
  • Caulk
  • 1 quart exterior grade white paint
  • 1 quart primer
  • Paint roller, pan
  • Wood glue
  • Hammer
  • Nails
  • Screws
  • Wood filler
  • Tape measure
  • Electric drill
  • Drill bits
  • Sand paper
  • Level


Measure the width of the window and cut the materials to your specific window dimensions.

1. Cut the boards

Remember: a window box can be extremely heavy once full of plants and soil. Exactly 160 pounds of dirt went into each of these planters. Test them out with bags of soil (or anything, really!) beforehand. We also made wooden brackets to support the weight of the boxes.

2. Start assembling

Place bottom of window box onto a flat surface. Clamp the front and back boards onto the table and against the bottom window box board to hold securely into place while you drill the front and the back boards onto the bottom board. Repeat for the side boards.

Adding trim provides a clean and finished look to your window boxes. To add trim, cut four pieces the length and height for each side of your window box. Secure into place with a nail gun.

3. Prime and paint

For a smooth finish, fill in any nail holes with the wood filler prior to painting. Make sure to sand down the wood filler once you have applied.

Using a paint brush, followed up a roller, apply the paint primer to the window boxes. Once paint is dry, apply the paint color. We had used white to match the trim on the cabin.

Make sure to sand down the entire window box prior to painting, as well as in between priming and painting.

4. Hang window boxes

Drill holes into the siding of where you are going to place the lag bolts. If you aren’t making window boxes as large as ours, you could also secure with screws and nails and secure with a 2×4 block behind the window box – and below the window – for support.

5. Create drainage

Drill holes straight through the bottom of the window boxes to allow for drainage. Drill a hole roughly around every 6 inches.

We waterproofed the boxes to ensure longer life and to protect the cabin so that the water didn’t leak onto the siding.

6. Fill window box

It helps to add an inch or so of gravel prior to adding in the dirt to allow for excess water to drain. Cover gravel with potting soil, add the beautiful flowers and water!

DIY window flower boxes are the perfect way to add a touch of nature and color to your home without having to sacrifice any floor space. Plus, you get the satisfaction of creating something beautiful with your own two hands!

So go ahead, plant those petunias and snapdragons, and watch as your windowsill transforms into a blooming paradise.

Who needs a trip to the botanical garden when you have your very own DIY window flower box?