Planter Bench A Diy Guide To Building A Wooden Oasis

Senior technical editor Mark Powers made the entire installation from rot- and weather-resistant cedar lumber using lap joinery, a sturdy construction method meant to keep the planter walls from bowing against pressure from roots, should you decide to plant trees. The cedar lumber for this planter bench costs far less than built teak furniture but is just as weather resistant.

How to Build a Planter Bench Overview

For the Cut List, scroll down to the bottom of this article.

How to Build Outdoor Planter Bench

1. Cut the Pieces

Using a miter saw, cut boards for the seat, seat frame, planters, and inner frame. Fasten or clamp a stop block to the work surface, as shown, so that you can cut pieces to equal lengths quickly and precisely.

2. Assemble the Seat Frame

Set the seat frame pieces on edge with the two sides and a center stringer sandwiched between the front and back boards. Drive 3-inch screws through the front and back boards and into the ends of the three crosspieces, as shown.

3. Pick a Location

Look for a flat spot and lay the seat frame on the ground. If you have an incline, place a 4-foot level lengthwise on the frame and stack 2×4s underneath the low end until it sits level. Count the number of 2×4s it takes to level the frame; you’ll need to add this number of courses to the downhill planter, front and back boards and into the ends of the three crosspieces, as shown.

4. Lay Out the Planter Bases

Stand the seat frame on edge to line up the planter boxes, and decide which end gets the tall one. Arrange four boards against the frame on the ground in a pinwheel brick pattern—a frame with each board butting into the tail edge of the next as you work clockwise. Line up the base of the tall one flush with the end of the seat frame; for the short planter, inset the base so that it lines up with the inside edge of the frame at the end, as shown. This overhang creates a decorative cap for the short planter.

5. Prepare the Base

Sink the head of a garden spade into the ground along the outline of each planter frame to create an accurate footprint. Set the boards aside.

6. Excavate the Soil

Place a tarp near your work area. Dig out the beds to a depth of 6 inches, piling the dirt on the tarp for easy removal. Keep the walls plumb and the bottom level.

7. Add the Bed Gravel

Add 2 inches of gravel in each hole and tamp it down to create a solid and level foundation for the planters. Add another layer and tamp it down, repeating as necessary until your bed of gravel sits 2 inches below ground level. Now add a ½-inch layer of sand or potting soil to make it easier to level your first course of each planter box.

Tip: If you don’t have a hand tamper, you can make do with a scrap block of 2×4. Use the end of the board to pack the gravel into a level field.

8. Establish the Base

Lay the first course in the footings in your pinwheel pattern. Place the seat frame on top of the boards to square them up, making sure it ends flush with the tall planter box and overhangs the short planter box slightly at the other end. Lift off the seat frame, and rest a level on the first course of boards. Strike them with a hammer to settle them into a level plane; sweep dirt or sand underneath the boards to fine-tune.

9. Lay the Second Course

Using a caulk gun, apply adhesive in a zigzag on top of the boards. For strength, lay the second course in the reverse direction so that each board overlaps a joint on the first course. This is lap joinery.

Tip: As you add courses, run a block along the corner joints to ensure that the ends of the lapped boards sit flush with the sides.

10. Secure the Courses

At each corner, sink 3-inch stainless-steel screws through the second course and into the first to secure the boards into one solid assembly.

11. Erect the Planters

Anchoring the planters will keep them from shifting out of place. Fit your drill with a paddle bit large enough to accommodate the spikes (we used a 3/8-inch bit). Drill a pilot hole all the way through the center of each side of the bases, as shown.

12. Drive the Spike

Hammer a spike into each pilot hole until its head sits flush with the surface. After each spike, use the seat frame to check for square and level, making adjustments as needed. Next, apply adhesive on the second course, and lay the next course of boards, continuing to lap the joints as like earlier. Nail the boards in place with 3-inch galvanized nails. Continue gluing and nailing courses, overlapping the joints with each layer, until the planters reach the height you want for the bench. (Nine courses above ground will give you a common bench height of around 18 inches.)

13. Assemble the Inner Frame

Since its boards sit on edge, you need an inner frame to make up for the width of the other courses. Place two crosspieces on edge flush to the inside walls of the planter, then cut two shorter pieces to fit between them, also flush to the inside walls. Mark where the pieces meet one another, remove them, screw them together, and pop the inner frame back into place. Screw through the seat frame into the inner frame’s crosspieces. To secure the assembly, drive 3-inch screws at an angle through the inside edges of the inner frame and into the planters, as shown. Now position, glue, and nail four more courses onto the box that will become the tall planter.

14. Install the Seat Boards

Add a frame stringer alongside the tall planter, but not touching it, to support the seat boards. Position them ¼ inch from the tall planter and overhanging the frame at the opposite end by 1½ inches. Leave a ⅜-inch gap between the boards, and let the front and back boards hang over the seat frame an equal distance. Sink 2-inch screws through the seat boards and into the framing.

Tip: Be sure to start with the clutch of your drill/driver on a low setting when driving stainless-steel screws—they strip easily.

15. Cut the Planter Opening

Peek between the seat boards, and lay out cutlines with a straightedge. Insert the jigsaw blade between the seat boards and cut along the inside edges of the planter, as shown.

16. Miter the Cap Pieces

On a 1¼x6 board, use a Speed Square to draw opposing 45-degree angles so that the distance from short point to short point equals the inside edge of the tall planter. Using a circular saw guided by the Speed Square, cut the lines. Repeat to create three additional cap pieces.

CUT LIST

2x4 planter pieces: 4 per course @ 16½ inches 2x4 seat frame front and back: 2 @ 82½ inches 2x4 seat frame crosspieces: 8 @ 17 inches 2x4 blocking: 4 @ 13 inches 2x6 seat boards: 4 @ 63 inches 2x6 cap: 4 @ 24 inches from long point to long point The dimensions of our finished bench: 84”L × 23”D × 18”H