How to Build a Simple Planter Box | Cut, Screw, Drain

Building a simple planter box comes down to five moves: measure your space, cut the boards, screw the frame together, add a bottom, and drill drainage holes. You don’t need fancy joinery or a workshop full of tools — a saw, a drill, and exterior screws get the job done for well under $50 in lumber.

What You Need Before You Start

Gather these materials and tools before you cut anything. The exact lumber size is flexible — 1×6 boards, fence pickets, or even ripped 2x4s all work — as long as the wood is rated for outdoor use.

• Lumber: dimensional boards like 1×6, 1×4, or fence pickets, cut to your planned length
• Exterior wood screws (1 1/2 to 2 inches) or galvanized nails — never indoor fasteners, which corrode outdoors
• Wood glue for extra joint strength
• Landscape fabric or plastic liner to protect the wood and keep soil in
• Pebbles or river rock for drainage (optional)
• Potting soil for planting
• Tools: circular saw or hand saw, drill, measuring tape, square, clamps

Scale these numbers to your own space — the logic stays the same at any size.

Step-by-Step Assembly

1. Measure the planting area. Determine the length, width, and height you want, then use those numbers to plan your front, back, and end pieces. This first step prevents the most common mistake — building a box that doesn’t fit its spot.
2. Cut all boards to size. Mark each piece with a square, then cut with a circular saw or hand saw. Cut the front and back to full length, the ends to your depth, and the bottom panel to the inner dimensions of the frame.
3. Mark and predrill pilot holes in the end pieces. Predrilling stops the wood from splitting and keeps your screws driving straight.
4. Assemble the frame. Apply wood glue to the joints, clamp the pieces, and drive screws through the end pieces into the front and back boards. Assemble so the boards with pilot holes sit on the outside corners. Check the frame is square before the glue sets.
5. Install the bottom board. Position it inside the frame on the inner lip, and secure it with screws from the outside or through the bottom.
6. Drill drainage holes. After the box is assembled, drill at least five holes in the bottom, each no more than 3/4 inch wide, spaced evenly. Skip this and water pools at the roots — root rot is the fastest way to kill a planter.
7. Add liner and drainage. Lay landscape fabric across the bottom and up the sides, then add a layer of pebbles if you like. Keep the fabric from blocking the drainage holes so water can still escape.
8. Finish and plant. If you’re painting or staining, do it after assembly and let it dry completely before adding soil — planting into wet finish ruins both the paint and the wood.

When the box is done, you’ll see a square, solid frame with the bottom panel firmly seated and water draining freely through the holes. That’s your success signal.

Choosing Between Wood Types

The wood you pick affects price, lifespan, and how the box looks. Cedar and redwood resist rot naturally but cost more; pressure-treated pine is cheaper and lasts years but contains preservatives some gardeners avoid near edible plants. If you want a finished look that still fits a modest budget, a simple planter box built from cedar pickets is the most common choice on gardening forums. A solid frame plus the right wood determines most of the box’s longevity.

Common Mistakes Worth Avoiding

• Skipping the measurement step — the box ends up too big or too small for its spot
• Cutting the bottom board to the outer width instead of the inner width — measure the inner dimensions before cutting
• Omitting drainage holes — waterlogged soil kills roots within weeks
• Failing to predrill — screws split the ends, especially on narrow boards
• Planting before the finish dries — wet paint traps moisture against the wood

If you’d rather skip the saw work and compare ready-made options, our roundup of the best simple planter boxes breaks down top picks by size, material, and price.