Build a Cedar Deck Planter with a Built-In Privacy Screen

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A cedar deck planter with a built-in privacy screen adds greenery and a little separation without fastening a tall panel to the house or deck railing. This plan makes a box 48 inches long, 16 inches wide, and 18 inches tall, with a slatted screen rising 36 inches above the box. It suits a confident beginner who can make square cuts and drive exterior screws. Build it on a dry day, then let the finish cure before filling it.

Plan the footprint and gather materials

Check the deck’s load capacity and choose a level spot near the railing, but leave room to reach the planter for watering and maintenance. Wet soil is heavy: a planter this size can weigh several hundred pounds when filled. Use a lightweight potting mix rather than garden soil, and don’t place the box where it blocks a door, drain, or required walkway.

Buy cedar boards that are reasonably straight and free of large knots at the joints. Rough-sawn cedar may be cheaper, but it can vary in thickness and make clean, flush corners harder. For a smoother beginner build, use 5/4-by-6-inch cedar decking for the sides and 2-by-2-inch cedar for the screen frame. A cedar deck board search can help compare board profiles and lengths; inspect lumber in person if possible.

The 13-inch end and bottom pieces fit between the long sides when the actual board thickness is about 1 inch. Measure your lumber before cutting; nominal sizes are not exact. You’ll also need exterior-rated screws, a drill, a saw, a square, a tape measure, and a 1/8-inch drill bit for pilot holes. Stainless-steel or coated deck screws resist corrosion better than interior screws.

Assemble a durable planter box

Cut the four long sides and four end pieces. Stack two side boards per wall to make an 11-inch-high box; the corner posts extend below the walls to lift the bottom off the deck. Set two posts inside each end corner and fasten the side boards into them with two screws per board end. Keep the post tops flush with the box rim and check each corner with a square as you work.

Fit the five bottom slats across the 13-inch opening, leaving roughly 1/4 inch between them for drainage. Screw each slat into both long sides. Don’t caulk the gaps: trapped water encourages rot. If you want a fabric liner, use breathable landscape fabric and leave the drainage openings clear. A plastic liner can hold water against the cedar unless it has generous drainage holes.

Sand splinters and sharp corners, but don’t round the edges so much that board joints become uneven. Cedar is naturally weather resistant, yet ground contact and standing water still shorten its life. Small plastic or rubber feet can help keep the box from sitting in puddles; they’re a useful upgrade on a wet deck, not essential on a well-drained surface.

Build and attach the privacy screen

Set the two 40-inch uprights against the inside faces of the long box sides, 6 inches in from each end. With 18 inches of each upright below the rim, 22 inches will rise above it. Fasten each upright through the planter wall and into its post with three exterior screws, spacing them vertically. This connection is stronger than attaching the screen to a single thin side board.

For a 36-inch screen above the rim, position seven 1-by-4 slats horizontally across the uprights, with about 1/2 inch between them. The slats span the 48-inch length, and their 3 1/2-inch face makes a screen roughly 27 inches tall. Center the slatted panel so its top sits about 36 inches above the planter rim, then screw each slat to both uprights. Pilot-drill near board ends to reduce splitting.

That slatted screen provides partial privacy while allowing wind through. Close-spaced boards block more sightlines but catch more wind and put greater leverage on the uprights and box. On an exposed deck, keep the gaps or shorten the screen rather than building a solid sail. If the screen will be tall or the site is very windy, add a third upright in the center and fasten the base to the deck only if the deck manufacturer and building rules allow it.

Protect the wood and fill the planter

Leave cedar unfinished for a natural silver-gray color, or apply a penetrating exterior stain to slow color change and reduce water uptake. Clear finishes need maintenance too, and many break down faster in direct sun. Choose an exterior product labeled for cedar, follow its coverage and curing instructions, and coat all accessible faces before assembly if you want more complete protection. An exterior cedar stain search is a starting point; the cheaper option is to leave the wood bare and accept the weathered look.

Set the finished planter in place before filling it. Add a layer of potting mix, then plant herbs, flowers, or compact shrubs suited to the deck’s sun exposure. Avoid packing soil into the screen uprights or over the bottom gaps. Water slowly and check that runoff drains freely; water pooling under the box is a sign to adjust the feet or move it.

Maintain it through the seasons

In spring, inspect screw heads, joints, and the screen uprights for movement or splits. Tighten loose fasteners and replace any corroded screws with exterior-rated ones. During summer, water as needed and keep drainage gaps open. In fall, remove dead plant material and clear wet leaves from the bottom. In cold climates, empty the planter or protect it from prolonged freeze-thaw cycles if the box will hold saturated soil.

Reapply stain only when water no longer beads or the color has visibly faded, following the finish maker’s directions. Cedar can crack as it dries; a small surface check is usually cosmetic, but a split at a screw or a wobbling screen upright needs attention. Fix it before wind loads or a heavy storm turn a minor repair into a broken panel.