What's inside
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This small cedar planter fits a patio, balcony, or narrow side yard and gives climbing plants a simple trellis to follow. The finished box is about 24 inches wide, 12 inches deep, and 48 inches tall to the top of the trellis. It is large enough for herbs, annual flowers, peas, or one compact cucumber plant without becoming too heavy to move.
Contents
Materials and Tools
Use 1×6 cedar fence boards or clear cedar boards for the planter sides. Fence boards are cheaper, but they often vary in width and may be rough or slightly cupped. Buy extra material so you can reject split boards. The trellis uses 1×2 cedar strips.
You will also need exterior-rated screws, a drill/driver, a 1/8-inch drill bit, a countersink bit, a tape measure, square, pencil, and saw. A box of exterior stainless or coated deck screws is a better choice than drywall screws, which rust and can snap outdoors.
A miter saw makes the repeated cuts quick, but a circular saw and straightedge work just as well. Use a waterproof exterior wood glue only as a supplement to screws. Glue alone is not a reliable outdoor joint, especially where wet soil keeps the wood damp.
Cut List
The measurements below assume boards close to 5-1/2 inches wide. Check your actual board width before cutting. The planter is built from three horizontal courses on each side, with a bottom set inside the box.
| Part | Quantity | Material | Length |
|---|---|---|---|
| Front and back boards | 6 | 1×6 cedar | 24 inches |
| Side boards | 6 | 1×6 cedar | 11 inches |
| Bottom slats | 3 | 1×6 cedar | 22-1/2 inches |
| Corner cleats | 4 | 1×2 cedar | 10-1/2 inches |
| Trellis uprights | 2 | 1×2 cedar | 40 inches |
| Trellis crosspieces | 5 | 1×2 cedar | 22 inches |
| Trellis top support | 1 | 1×2 cedar | 22 inches |
The 11-inch side boards create a finished box close to 12 inches deep once the front and back boards are included. If your boards are a different width, make the bottom slats about 1/2 inch shorter than the inside width of the box.
Cedar and Fastener Choices
| Choice | Cost | Advantages | Drawbacks |
|---|---|---|---|
| Rough cedar fence boards | Lowest | Good rot resistance; easy to find | Variable width, knots, rough surfaces |
| Clear cedar boards | Higher | Straighter, smoother, fewer defects | Costs more; unnecessary for a rustic planter |
| Coated exterior screws | Low to medium | Fine for most outdoor projects | Can stain cedar or eventually corrode |
| Stainless steel screws | Highest | Best corrosion resistance and clean appearance | More expensive and easier to strip |
The cheaper fence-board option is fine if you sort through the stack and let the wood dry before building. Avoid boards with long cracks, soft spots, or severe cupping. Cedar contains tannins that can react with ordinary steel, leaving black marks around the screw heads. If appearance matters, use stainless screws or quality exterior screws labeled for cedar.
Build the Planter Box
Cut the six front, back, and side boards. Lightly sand splinters, but do not round the edges heavily; square edges make the courses line up more cleanly. Build the first course by placing one front board between two side boards, or place the side boards between the front and back boards and keep that orientation for all three courses.
Pre-drill two holes at each corner, about 3/4 inch from the board ends. Drive 1-1/4-inch screws through the front and back boards into the side-board ends. Check the box for square by measuring both diagonals. If the measurements differ, push the longer diagonal inward before tightening the screws.
Stack the second and third courses, staggering the corner joints if possible. A small 1/16-inch gap between courses is acceptable and helps the wood dry. Do not force severely bowed boards into alignment; they will pull the box out of square or split around the screws.
Attach the four 10-1/2-inch corner cleats inside the box. Set each cleat flush with the top edge and screw through the planter walls into it. These cleats reinforce the corners and support the bottom. Set the three bottom slats across the cleats, leaving roughly 1/4 inch between slats for drainage. Drill several 3/8-inch drainage holes through each slat.
Add the Trellis Back
Place the two 40-inch uprights against the outside of the back wall, aligned with the side edges. Let about 12 inches extend above the planter. Use two screws through each upright into every back-board course. If the planter will hold a vigorous vine, add a small bead of exterior glue behind each upright and use longer screws that still do not protrude into the soil.
Mark the crosspieces at 8-inch intervals, beginning about 4 inches above the planter rim. Fasten the five crosspieces between the uprights, then attach the top support near the uprights’ ends. Keep the trellis face flat while driving screws. A bowed trellis catches wind and places unnecessary leverage on the planter wall.
For very windy locations, add two diagonal braces from the back of the planter to the uprights, or anchor the planter to a wall. A trellis loaded with wet foliage can act like a sail. Do not rely on the planter’s weight alone on a balcony or exposed deck.
Finish and Planting
Leave cedar unfinished for the simplest maintenance. It will weather gray but remain useful. A penetrating exterior oil can preserve more color, though it must be renewed and should be labeled safe for garden use. Avoid paint or finishes on the inside surfaces unless the product specifically suits raised garden beds.
Line the bottom with landscape fabric only if you want to keep soil from washing through; do not seal the drainage holes. Fill with a quality container mix rather than heavy garden soil. The planter needs about 4 cubic feet of mix, depending on the actual interior dimensions. Keep the box slightly off a wet surface with cedar scraps or plastic feet, and inspect the bottom each spring. Replace a bottom slat when it becomes soft instead of waiting for the whole box to fail.
Build in early spring for peas and cool-season greens, or wait until the danger of frost passes for cucumbers, beans, and flowering annuals. The trellis is strongest with lightweight annual vines; woody perennial vines will eventually exceed the capacity of this small planter.