Cedar is one of nature's great gifts to outdoor woodworkers. It's naturally resistant to rot, insects, and moisture — which means this planter will look great for years without any chemical treatment. And it smells absolutely wonderful while you're building it.
This project is ideal for apartment dwellers, renters, or anyone with a small outdoor space who wants to grow herbs, vegetables, or flowers. The proportions are designed to sit on a balcony railing ledge or stand alone on a patio, and the wood develops a gorgeous silver-grey patina over time if left untreated — or stays warm and golden if you apply an exterior finish.
What You'll Need
🌲 Materials
- Cedar 1×6 boards — two 8-foot lengths
- Cedar 1×2 for corner bracing
- Exterior wood screws — 1¾" (box of 50)
- Landscape fabric (optional but recommended)
- Exterior wood glue
- Drill + bits
- Miter saw or hand saw
- Clamps (4 recommended)
- Sandpaper — 120 and 180 grit
- Exterior finish (teak oil or leave raw)
- Tape measure and pencil
- Speed square
Cut List
From your 1×6 cedar boards, cut the following pieces. (Actual cedar 1×6 is ¾" thick × 5½" wide.)
✂️ Cuts
- Long sides (×2): 24" long
- Short sides (×2): 10½" long
- Bottom slats (×3): 10½" long
- Corner cleats (×4): 10½" from 1×2
Step-by-Step Instructions
Cut all your pieces first
Measure and cut all pieces before assembling — "measure twice, cut once" is especially true with cedar, which is pricier than pine. The easiest approach: write down your cut list and take it to the hardware store or lumber yard. Most will cut everything for you for free or a very small fee. If you're cutting at home, a simple hand saw works perfectly — just draw a clear straight line first and take your time.
Sand all pieces while flat
Sanding is much easier before assembly. Run 120-grit over all faces and edges, then 180-grit on the faces that will show. Round over the top edges with 120-grit so they're comfortable to touch. Cedar splinters can be nasty, so gloves and a light sanding go a long way.
Attach corner cleats to the short side boards
The 1×2 corner cleats are the backbone of the box. On the inside face of each short-side piece, position a cleat flush with each end — these will give you something solid to screw the long sides into. Use two exterior screws per cleat plus a dab of exterior wood glue. Clamp while the glue sets. Pre-drill all holes to prevent splitting.
Assemble the box sides
Stand two short-side panels upright. Bring a long-side board up to the outside of the cleats and clamp in place. Drive two exterior screws through the long side into each cleat. Repeat for the second long-side board. You now have a four-sided box frame — check it's square by measuring corner to corner diagonally. Both measurements should be equal.
💡 Square Check: If the box is out of square, place it on a flat surface and gently push one corner diagonally until both measurements match. Then add your bottom slats to lock it in place.
Add the bottom slats with drainage gaps
Lay the three bottom slats across the inside base of the box with a ½" gap between each — use a scrap piece of ½" wood as a spacer. These gaps are essential for drainage; a planter with no drainage will rot roots fast. Screw each slat down through its ends into the short-side boards. You can also cut an internal ledge from scrap cedar to support the slats if needed.
Line with landscape fabric (optional)
Cut a piece of landscape fabric to fit inside the box and up the sides about 2". This prevents soil from washing out the drainage gaps while still allowing water to pass through. Staple it lightly or simply tuck it in — the soil weight holds it fine. Skip this step if you're planting in pots placed inside the box rather than directly in soil.
Finish and fill
If you want to preserve the warm cedar color, apply one coat of exterior teak oil or cedar sealer and let dry for 24 hours before adding soil. If you love the natural aging process, leave it raw and enjoy watching it silver over the seasons — this is actually the more eco-friendly choice. Fill with quality potting mix, leaving 1" of space below the rim.
What to Plant
This planter size is perfect for a wide range of plants. Here are our top picks:
Fresh Herbs
Basil, rosemary, thyme, mint (keep mint separate!)
Strawberries
Everbearing varieties do great in compact planters
Salad Greens
Lettuce, arugula, spinach — great for cut-and-come-again
Pollinators
Lavender, calendula, or cosmos to attract bees
Peppers
Compact pepper varieties love the confined root space
Bulbs
Tulips, daffodils — plant in fall for a spring surprise