3-Season Planter Box Plans

Enjoy lush, blooming plants spring, summer and fall

Plastic planters or liners keep wet dirt away from wooden parts. And because plastic containers come in various shapes and sizes, you have a lot of freedom in designing your planter.

By the DIY experts of The Family Handyman Magazine






$20 - $100

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This planter has a secret inside

It's lined with an ordinary plastic planter box, the kind you can get at any home or garden center for about $10. That means you can lift out one plastic box and drop in another, instantly swapping plants. You might, for example, start the growing season with spring bloomers in your planter while the other plants grow elsewhere. When the spring plants are past their prime, you can drop in the next set of plants.

The inner plastic box has practical advantages too. It separates damp soil from the wooden planter, which protects the wood from moisture problems like rot and peeling paint. And since this planter is really just a decorative container for the plastic pot, it's much easier to build than a typical planter. If you use cedar lumber, this project will cost you about $100. Built from pressure-treated or untreated pine, it will cost about $80.

Step 1: Build the box

The core of this planter is a box made from 3/4-in. CDX or BC plywood. Most home centers and lumberyards will sell you a partial sheet of plywood and cut it into manageable sizes for you to haul home. Cut plywood pieces to final size with a table saw, or clamp a straightedge to the plywood and cut it with your circular saw. Assemble the box with water-resistant wood glue and 6d galvanized box nails or exterior-grade screws (Photo 1).

Step 2: Add the braces

Add plywood braces inside the long planter to square the box and hold the long sides straight. We centered our braces, but you can shift them down if they obstruct the liner (Photo 2). The other two planters don't need braces if you make sure they're square after you assemble them. Check with a framing square and add braces if they're needed.

Step 3: Assemble the legs

We used 5/4x6 (1-in. x 5-1/2-in. actual dimensions) cedar decking for the legs, but you can substitute other 5/4 decking. First rip the deck boards to 5-1/4 in. to remove the rounded corners on one edge. Then run the squared edge against the table saw fence when you rip the 3-in.- and 2-in.-wide leg pieces. Cut the pieces to length and then glue and nail them together with 8d galvanized casing nails (Photo 3).

Beadboard planter

Beadboard planter

Step 4: Attach the legs

Sand the saw marks from the board edges before you screw the assembled legs to the box (Photo 4).

Step 5: Bevel the cap boards

Ripping the bevel on the 2x4 top cap (Photo 5) may require you to remove the blade guard as we did. If so, use extreme caution to keep your fingers well away from the blade. Make sure the blade is tilted away from the fence as shown in the photo. Mount a featherboard and use push sticks to complete the cut. Start the cut by pushing with your back hand while holding the board down with a push stick in your front hand. Keep a second push stick within easy reach. When your back hand gets to the rear edge of the table saw, pick up the second push stick and use it along with the front push stick to push the board clear past the saw blade. Keep your attention focused on the saw blade at all times. Shut off the saw and wait for the blade to stop before retrieving the beveled board.

Step 6: Assemble the cap

Photo 6 shows how to assemble the top cap pieces into a frame that's easy to attach to the box. Start by gluing the miters and clamping one long side as shown. Then drill 1/8-in. pilot holes for the nails. Drive a pair of 8d galvanized casing nails from opposite sides at each corner to pin the miters together. Offset the nails slightly so they don't hit each other.

Step 7: Attach the cap

Mount the frame to the box by centering it with an even overhang all around and nailing it down with 12d galvanized casing nails (Photo 7). Measure and drill 5/32-in. pilot holes for the nails, making sure they're centered on the top edges of the plywood.

Step 8: Add siding to complete the planter

Beadboard is great for a traditional-looking painted planter. For the best-looking planter, plan ahead and cut the first and last boards to equal width. Start by nailing the top trim (H) to the plywood box with 4d galvanized casing nails. Use a precut length of beadboard as a spacer to position the bottom board precisely. When you glue in the beadboards, be sure to leave a 1/8-in. space at each end to allow room for expansion (Photo 8). Fill the space with caulk before painting.

Lap siding planter

We sided the tall box with 1/2-in. x 3-1/2-in. cedar lap siding. Simply cut the siding to fit between the legs. Rip a 1-in. strip off the thin edge of a siding piece for a starter. (Rip the leftover to fit at the top later.) Nail the starter strips along the bottom of the plywood (under the first row of siding) to hold the first piece of siding at the correct angle. Predrill 1/16-in. holes 3/4 in. from the end and 5/8 in. from the bottom of each piece to prevent splitting. Then nail on the siding with 4d galvanized box nails. The top cap on this planter fits flush to the inside edge of the plywood box, which may cause the nails protruding through the inside to interfere with the plastic planter. If so, bend them flat or clip them off. You'll save measuring time by making a simple spacing jig as shown below. We finished this planter with transparent deck stain.

Lap siding planter

Lap siding planter

Cedar shingle planter

Wood shingles are perfect for a rustic-looking box. And finishing the planter is a snap if you use deck stain like we did. The only drawback to shingles is that you may have to buy a whole bundle, many more than you'll need to side one planter.

The butt end of shingles is a little too thick for the proportions of this planter. So before cutting the shingles to their final length, trim off about 4 in. from the thick end (assuming your shingles are about 16 in. long). Then cut and install them as shown.

Start with a double thickness of shingle on the first row. Then offset the joints by at least 1-1/2 in. from one row to the next. Also stagger the shingles up and down if you like the "shaggy" look. Nail the shingles to the plywood box with 3d galvanized box nails. Position the nails so the next row will cover them. The nails will stick through the inside of the box but won’t interfere with the plastic planter box.

Cedar shingle planter

Cedar shingle planter

Additional Information

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Basic hand tools
  • Drill/driver, cordless
  • Table saw

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