What's inside
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Contents
Plan the planter and choose a location
This raised herb planter uses four corner posts joined by horizontal cross rails. The frame is straightforward to build with a circular saw or handsaw, drill, and square. For a useful starting size, make the outside dimensions 48 inches long by 24 inches wide and about 30 inches tall. That gives you room for several herbs without making the box difficult to reach across.
Place it where herbs will get at least six hours of sun, with a clear path to water. A filled planter can weigh well over 200 pounds, so build it close to its final spot rather than planning to move it. If the ground is uneven, level a compacted gravel pad or use pavers under the posts before assembly.
Materials and cut list
Use untreated, rot-resistant lumber for any boards that touch soil. Cedar is easy to work with and reasonably durable; untreated pine costs less but is more likely to decay, especially where it stays wet. Avoid lumber treated with preservatives unless its labeling specifically says it is suitable for garden beds. Line the inside with breathable landscape fabric to slow soil loss, not plastic, which can trap water against the boards.
| Part | Quantity | Suggested size |
|---|---|---|
| Corner posts | 4 | 2×2×30 inches |
| Long rails | 4 | 1×6×48 inches |
| End rails | 4 | 1×6×21 inches |
| Bottom slats | 5–6 | 1×4, cut to fit inside frame |
| Fasteners | As needed | Exterior-rated screws, about 2½ inches |
The cut sizes above assume the long rails run outside the posts and the end rails fit between them. A 2×2 is actually about 1½ inches square, so the end rails should be about 21 inches long to create a 24-inch outside width. Measure your actual lumber before cutting; rough or undersized boards can change the fit. For more consistent cuts, a circular saw for woodworking is convenient, but a hand saw works for this small cut list.
Tools and fasteners
Gather a drill/driver, tape measure, pencil, square, clamps, and safety glasses. Choose exterior-rated screws—coated deck screws or stainless steel—for joints exposed to moisture. Plain interior screws can rust and stain the wood; brittle drywall screws may snap as the frame shifts. A basic box of exterior deck screws is usually enough. Stainless steel costs more but is a sensible choice near salty air or persistently damp conditions.
Assemble the corner-post frame
Cut all four posts to the same length and check each cut end for square. Lay two posts on a flat surface. Position two long rails against their outside faces, one near the top and one near the bottom, leaving the lower rail about 2 inches above the post ends. The gap gives the bottom slats a place to sit and keeps them off the ground.
Predrill two pilot holes at each rail-to-post connection to reduce splitting, especially in cedar. Drive the screws straight and snug, not so hard that they crush the wood. Repeat with the other long side. Stand the two sides up, fit an end rail between the posts at each end, and check the corners with a square before driving screws. Measure both diagonals; if they match, the rectangle is square. Correct any twist now, before adding the bottom.
Fit the bottom and allow drainage
Measure the inside opening and cut five or six 1×4 slats to fit across the short dimension. Leave roughly a ⅛- to ¼-inch gap between slats so water can drain. Attach each slat to the lower rails with two screws at each end. Do not use a solid plywood bottom: it holds water, adds weight, and can fail quickly outdoors. If the planter will sit on a deck, set it on a tray or protective feet and check that runoff will not damage the surface.
Staple landscape fabric loosely over the inside bottom and lower walls, trimming it so it does not cover the drainage gaps. Fabric helps keep potting mix from washing through, but it is not a structural liner and will eventually need replacing.
Fill and plant the box
Set the planter in its final position and check it for wobble. Add thin shims under a post if needed; a rocking box can loosen screws as the soil settles. Fill with potting mix intended for containers rather than dense garden soil, which can compact and drain poorly in a raised box. Leave about 1 inch of space below the rim to make watering easier.
Group herbs by water needs. Rosemary, thyme, and oregano prefer sharper drainage and drier soil than parsley, basil, and chives. You can plant the drier herbs at one end and water that area less, or use separate pots set into the planter. A simple container-garden potting mix is a practical choice; buying a premium mix is not necessary if it drains well and you are willing to refresh it each season.
Choose a material for your conditions
| Material | Cost and work | Best fit |
|---|---|---|
| Cedar | Higher upfront cost; easy to cut and screw | A planter expected to stay outdoors for several seasons |
| Untreated pine | Cheapest and widely available; shorter service life in wet conditions | A low-cost trial build or a sheltered spot |
| Composite boards | Often costly; may need different fasteners and support spacing | A low-maintenance appearance where board specs suit the design |
Regardless of material, inspect the joints each spring and tighten any loose screws. Keep soil from sitting above the top rail, and remove standing water around the feet. The main failure points are trapped moisture, split posts from unpiloted screws, and an out-of-square frame that racks under the weight of wet soil. Careful layout and drainage do more for service life than decorative trim or a thick coat of finish.