Step-by-step tutorial: Build a charming window box from scrap wood to boost curb appeal
We love turning thrifted finds, cast-off lumber, and leftover paint into small, impactful projects. Recently we refreshed our backyard pool shed and found it still needed a finishing touch—so we built window boxes from scrap wood to add instant charm and curb appeal.
These window boxes were made almost entirely from leftover fence boards and extra paint, so the project cost was minimal. If you have a pile of scrap wood and a little time, this is an easy DIY that makes a big visual difference for exterior windows.
Why build a DIY window box?
Window boxes instantly soften and enliven a façade. Building your own from scrap wood is eco-friendly, budget-friendly, and customizable to any style or size of window. Using recycled materials lets you create a unique look while saving money compared to store-bought planters.
Supplies used
- Four fencing boards (or similar scrap planks; adapt sizes as needed)
- 1×2 boards for corner and edge trim
- Tape measure
- Circular saw (or table saw)
- Brad nailer or hammer
- Power drill/driver and drill bits
- Wood screws and finishing nails
- Square and framing square
- Galvanized L brackets for mounting
- Pencil, wood filler, and medium-grit sandpaper
- Primer and exterior paint (or paint sprayer)
- Window box liner, potting soil, and your choice of flowers
The steps to build a scrap wood window box
1. Measure the window box liner first. Measure its width, length, and depth, then add the thickness of your side boards (we added about 1/4″ extra for an easy fit). These dimensions determine your wood cuts.
2. If any boards are wider than you need, rip them down the center with a circular saw or table saw to create the correct width for your sides.
3. Use a pencil and square to mark each piece according to the measurements you recorded. Accurate marks make cutting and assembly much easier.
4. Cut all pieces to size with your circular saw.
5. Assemble the box by screwing the end pieces to the longer front and back boards at right angles. Repeat on the other side until you have a four-sided box.
6. Reinforce corners and finish the edges with 1×2 trim pieces cut to length and attached along the top, bottom, and side edges. If you are stacking two smaller boxes to create one deeper box, use the 1×2 trim to secure them together. Leave the back side that sits against the wall flush without 1×2 trim so it fits snugly against the window.
7. On the bottom, cut and install three slatted boards with gaps between them to allow water drainage. Secure them with screws from the underside.
8. Fill screw holes with wood filler, let dry, then sand smooth. This creates clean edges and prepares the surface for paint.
9. Prime the assembled box, then paint with exterior paint. Choose a color that complements your home or pool shed for maximum curb appeal.
10. Mount the window box with galvanized L brackets attached under the window sill. If your windows are low to the ground, you may need to position the brackets differently so the box sits at the desired height.
11. Set the box on the brackets and secure the bracket to the bottom of the box with screws. Enlist a helper if needed to hold the box steady while you fasten it.
12. Insert your plastic or fabric window box liner, drill large drainage holes in the bottom of the liner, then fill with potting soil and plant your flowers.
Final thoughts
These scrap wood window boxes added a lot of personality to our pool shed and cost only a fraction of store-bought options. They’re not perfect—made from leftovers—but they’re sturdy, attractive, and eco-conscious. With primer and a few coats of exterior paint, they’ll hold up through the seasons.
If you’ve made anything from scrap wood, we’d love to hear about it. Small projects like this are a great way to use leftovers, save money, and improve curb appeal at the same time.
