Sturdy Deck Planter

Updated: Jul. 20, 2023

This easy-to-make flower box sits on almost any deck rail … or can even stand alone

sturdy deck planter flower box
Looking for a planter box that fits in just about anywhere? Then this sturdy and attractive planter box is what you need.

You might also like: TBD

Build a Sturdy Deck Planter

This sturdy deck planter has a clever design so it can rest securely on a 2×4 or 2×6 deck railing or sit on a patio, porch or deck floor without tipping. Plus, it can be made just about any length you want. If that’s not enough to get you building, it’s easy to make, even for first-time woodworkers. You won’t need a boatload of tools, either. A table saw is a must, but if you don’t have one, perhaps a neighbor or friend can help. Spend a few extra dollars on cedar, redwood or cypress. These woods hold up better to the moisture they’ll face from watering flowers. To attract more birds to your deck, learn how to build a bird house.

Here’s How to Build It:

cut ends with pattern deck planter

1. Cut Out End Pattern

Enlarge the end pattern (Figure B, in Project PDF’s below) to exactly 10-7/8 in. Cut two boards to a length of 12 in. and tape or glue the patterns onto the boards. With a saber saw or band saw, cut each end (A) using the pattern as a guide.

Mark the length of your box on boards four times, for parts B, C and D, avoiding knots at the ends; cut to length. The planter box shown is 24 in. long.

wood glue deck planter box

2. Glue Joints

Stand each end with the top edge down on your workbench and space them apart the length of the bottom board. Center the bottom board on each end and drill pilot holes to avoid splitting the wood. Use waterproof construction adhesive on all joints (Photo 2) before nailing pieces in place.

deck planter railing

3. Attach Railing Sides

On a table saw, cut the bottom board (B), slats (C) and railing spacers (D) to width. See Cutting List (below). Cut the railing sides (E), putting a 35-degree bevel along one edge. Be careful here—remember one side is rough and the other smooth. You can have either side facing out, but be sure to cut the angles the proper direction so the finish you prefer faces out.

Attach railing sides to the bottom. The beveled edge allows the sides to fit snuggly against the curved bottom of each end.

deck planter flower box

4. Nail Side Slats

Nail side slats starting from the top of the box, working your way toward the bottom. Remember, pilot holes are a must when nailing close to the ends of these pieces.

deck planter flower box rails

5. Add Rail Spacers

The spacers should be attached to the inside of each railing side as shown in Photo 5. These spacers strengthen the railing sides and also allow the box to snuggly hold onto a 2×4 deck rail. If you’re applying a stain or sealer to help protect the wood, allow the adhesive to dry 24 hours.

In the meantime, go to the garden center for some potting soil and colorful flowers to brighten up your deck, patio or porch.

Project PDF’s

Click the links below to download the construction drawings, materials list as well as the cutting list for this project.

Figure A

Figure B

Shopping list:

  • *1×8 x 10′ rough cedar, redwood or cypress (for 24″ planter)
  • 1 box 1-1/2″ galvanized finishing nails
  • 1 tube Waterproof construction adhesive
  • One qt. Clear sealer or deck stain (Optional, we applied three coats of Minwax Clear Shield.)

*Quantity is determined by the length of your box

Cutting list:

Key    |    Qty.     |    Size & description

A        |      2       |     enlarge Figure B to 10-7/8″ wide (ends)

B        |       1      |     5-5/8″ x 24″* (bottom)

C        |      8       |     1-3/8″ x 24″* (slats)

D        |      4       |     1″ x 5-1/2″ (spacers)

E        |       2       |      3-3/8″ x 24″* (railing sides)

*Length should be adjusted equally on pieces B, C and E.