How to Build a Raised Planter Box

A solid raised planter box comes down to four things: rot-resistant wood, a frame that won’t rack, drainage that actually drains, and enough soil depth for what you’re growing. Build a 2×4-foot elevated standing planter at roughly 30 inches tall out of cedar and you’re looking at one Saturday, about $90 to $130 in materials, and a planter that’ll outlast a decade of seasons. This guide walks the full build—the legged standing version your back will thank you for, plus a ground-level raised bed variant if you’d rather skip the legs.

Standing Planter vs. Ground-Level Raised Bed

Decide which you’re building before you buy a board, because the two are different animals. An elevated standing planter is a box on legs—usually waist-high—with a slatted bottom that holds a shallow tray of soil. You weed and harvest standing up, it keeps lettuce off the ground and away from a lot of pests, and it fits a patio or deck. The tradeoff is soil volume: you can’t realistically carry a foot of wet soil on legs, so you cap depth around 8–10 inches.

A ground-level raised bed is a bottomless frame sitting on soil—open at the base so roots run straight into the ground below. It holds far more soil, drains into the earth, and is dead simple to build. The downside is you’re bending over to tend it, and it has to live on dirt, not a deck. Most folks want the standing planter for a patio and a raised bed for a backyard plot. I’ll detail the standing build fully, then give you the raised-bed adjustments at the end.

One rule for both: keep wood off your house and away from constant moisture. Don’t butt a planter tight against siding where it traps water against the wall and invites rot and termites. Leave a few inches of gap so air moves and the wall can dry.

Choosing Your Wood

For anything holding soil and water, you want a species that resists rot without chemicals. Cedar and redwood are the standards—the heartwood contains natural oils that fend off decay and insects, and they’re completely food-safe. Western red cedar is the most common and affordable of the two; redwood looks gorgeous but runs pricier and is harder to find outside the West Coast. Expect untreated cedar 1×6 boards to run roughly $1.75–$3.50 per linear foot depending on grade and your region.

Now the pressure-treated debate. The old stuff—lumber treated with creosote or chromated copper arsenate (CCA, the green-tinged wood from before 2004)—leached arsenic and has no business near food crops. If you inherit an old planter built from railroad ties or vintage treated lumber, don’t grow edibles in it. Modern pressure-treated lumber uses ACQ (alkaline copper quaternary) or copper azole, which dropped the arsenic. It’s far safer, and many gardeners use it for the frame structure without issue. Still, copper does migrate slowly into soil, so if you’re growing food and using ACQ lumber, line the interior to put a barrier between the wood and the root zone.

On lining and food safety: use a permeable landscape fabric (weed barrier) against the wood, not solid plastic sheeting. Plastic traps water against the boards and rots them from the inside while drowning your roots—it defeats the whole point. Fabric lets water pass through while keeping soil off the wood and slowing any chemical contact. If you want a heavier barrier for treated lumber, a food-grade pond liner with drainage holes punched in the bottom is an option, but honestly, cedar plus fabric is the cleaner answer for edibles.

My default recommendation: untreated cedar for the whole thing if you can swing it, fir or pine for the legs only (they’re protected from soil and dry fast), and landscape fabric as the liner. That’s a food-safe, long-lived box without overthinking it.

Tools You’ll Need

• Circular saw or miter saw — a miter saw makes cleaner, faster crosscuts, but a circular saw with a speed square as a cut guide works fine.
• Drill/driver — one for pilot holes, one for driving screws is ideal; one will do if you swap bits.
• Speed square or combination square — for square cuts and checking corners at 90 degrees.
• Tape measure
• Level — to set the legs even so it doesn’t rock.
• Clamps — a couple of bar clamps to hold pieces while you screw them; saves a second pair of hands.
• Sandpaper or sanding block — 80- and 120-grit to knock down splinters and ease sharp edges.
• Drill bit set — including a 3/8-inch or 1/2-inch bit for drainage holes if you add a solid bottom.
• Pencil and a rag

Materials & Cut List (2×4 ft Standing Planter, ~30 in Tall)

This builds a planter with an outside footprint of about 24 x 48 inches, legs bringing the soil box to a comfortable 30-inch working height, and a soil tray roughly 9 inches deep. Dimensions assume nominal lumber (a “1×6” is actually 3/4 in thick by 5-1/2 in wide; a “2×4” is 1-1/2 x 3-1/2).

Lumber

• Cedar 1×6 boards — for the box sides. You’ll need two rows high (about 11 in of side wall). Buy four 8-ft 1x6s.
• Cedar or fir 2x4s — for the four legs and the bottom support rails. Buy three 8-ft 2x4s.
• Cedar 1×4 or 1×3 boards — for the bottom slats. Buy three 8-ft pieces (or rip down a couple of 1x6s).
• 2-1/2 in exterior screws — coated deck screws or stainless. One 1 lb box. Use stainless or coated only—plain steel rusts and streaks cedar.
• 1-5/8 in exterior screws — for attaching thin bottom slats. Small box.
• Landscape fabric — about 2 yards of permeable weed barrier for the liner.
• Optional: 4 locking casters (heavy-duty, 200+ lb rated total) if you want to roll it.

Cut List

• Long side boards: 4 pieces of 1×6 at 48 in (two rows on each long side).
• Short end boards: 4 pieces of 1×6 at 22-1/2 in (so the ends tuck inside the long sides; adjust to 24 in if you prefer ends outside).
• Legs: 4 pieces of 2×4 at 30 in.
• Bottom support rails: 2 pieces of 2×4 at 45 in, running the length under the slats.
• Bottom slats: roughly 8–10 pieces of 1×4 at 22-1/2 in, spaced with 1/4–3/8 in gaps for drainage.
• Corner cleats (optional but recommended): 4 pieces of 2×2 or ripped 2×4 at 11 in to reinforce inside corners.

Step-by-Step Build

1. Cut everything first

Make all your cuts before you start assembling. Measure twice, gang-cut pieces of the same length together so they match, and lightly sand every cut end and edge—cedar splinters love bare forearms. Lay the parts out in piles by type so you’re not hunting for the next board mid-assembly.

2. Build the four side panels into a box

Take your corner cleats (the 11-in 2x2s) and stand one upright at each end of a long side. Screw two 48-in 1x6s to the cleat, stacked to form an 11-in-tall wall, keeping the top edges flush. Repeat for the other long side. Now you have two long walls each with cleats at both ends. Stand them parallel and screw the 22-1/2 in end boards into the exposed faces of the cleats, closing the box. The cleats are doing the real work here—they give the screws something solid to bite into so the corners don’t pull apart when the box is full of wet soil. Check the box for square with your speed square before driving the last screws; a box that racks out of square will never sit flat.

3. Add the bottom support rails

Flip the box upside down. Run the two 45-in 2×4 rails along the inside bottom edges of the long walls, screwing them through the side boards into the rail. These rails carry the weight of the soil and slats and transfer it to the legs. A 2×4-ft box of wet soil is heavy—easily 150–250 lbs—so don’t skip this. Sink the screws snug but don’t strip the cedar.

4. Attach the legs

With the box still upside down, set a 30-in 2×4 leg vertically into each inside corner, snug against the corner cleat and the support rail. Screw through the side boards and through the rail into the leg from two directions so each leg is locked in both axes. Use at least four screws per leg. The legs should run from the top of the box down to the floor; the soil box ends up at roughly 30 in, which is a comfortable standing height for most people. Turn the planter right-side up and set it on a flat surface—check with a level and shim or trim a leg if it rocks.

5. Lay the bottom slats with drainage gaps

Lay the 22-1/2 in 1×4 slats across the support rails, running side to side, and screw each one down with the 1-5/8 in screws. Space them with a consistent 1/4–3/8 in gap between boards—a pencil or a couple of stacked washers makes a handy spacer. Those gaps are your primary drainage. Don’t lay them tight; water has to get out, and a sealed bottom will turn your soil into a swamp and rot the slats.

If you’d rather use a solid plywood bottom (cheaper, but shorter-lived), use exterior-grade plywood and drill a grid of 1/2-in drainage holes every 4–6 inches across the whole bottom. Slats are the better long-term choice—they drain freely and dry out instead of holding rot against the wood.

6. Line the interior

Cut your landscape fabric to drape up all four interior walls and across the slatted bottom, leaving a couple of inches to fold over the top edge. Staple it to the inside of the walls near the top rim. The fabric keeps soil from washing out through the slat gaps while letting water drain freely. Again—fabric, not plastic. Trim the excess at the top so it doesn’t show.

7. Optional: add casters and finish

If you want to move the planter to chase the sun, screw four heavy-duty locking casters to the bottoms of the legs. Use casters rated for at least 200 lbs combined and lock at least two of them. For finish, you can leave cedar bare—it weathers to a pleasant silver-gray—or coat the exterior only with a food-safe outdoor oil or a clear water-based exterior sealer to keep the color. Never coat the soil-facing interior surfaces with anything that isn’t food-safe.

Drainage Done Right

Drainage is where most planters fail. You’ve already built three layers of it: the gaps between bottom slats, the permeable fabric liner, and—optionally—a thin 1-inch layer of pea gravel or coarse perlite in the bottom of the soil tray to keep the drainage path open and stop fine soil from packing against the fabric. Don’t fill a quarter of the box with gravel, though; that old “gravel for drainage” advice creates a perched water table and actually holds water higher in the soil. A thin layer at the very bottom is plenty. The real fix is the open slat bottom letting water fall straight through.

For a ground-level raised bed, drainage is even simpler—it’s bottomless, so water sinks into the soil beneath. Just make sure you’re not building it over compacted clay or a paved surface that won’t drain.

How Deep, and How Much Soil?

Match your depth to your crops:

• Leafy greens, lettuce, herbs, radishes: 6–8 inches is plenty.
• Most vegetables—peppers, bush beans, bush tomatoes: 10–12 inches.
• Root crops and deep feeders—carrots, potatoes, full-size tomatoes: 12 inches and up.

Our standing planter gives about 9 inches of soil depth—ideal for greens, herbs, and shallow vegetables. If you want carrots or potatoes, build the ground-level raised bed deeper instead, since legs can’t safely carry a foot-plus of saturated soil.

To calculate fill volume: length x width x soil depth, all in feet, gives cubic feet. Our box is 4 ft x 2 ft x 0.75 ft (9 in) = 6 cubic feet. Bagged raised-bed mix usually comes in 1.5- and 2-cubic-foot bags, so you’d need three or four bags. For a good mix, aim for roughly 40% quality topsoil, 40% compost, and 20% aeration (perlite, coarse sand, or vermiculite). A purpose-blended “raised bed mix” already does this for you. Skip straight potting soil for a box this size—it’s expensive and too light—and skip pure topsoil, which compacts. If you want to grow watermelon or other sprawling crops, you’ll need a far bigger footprint; see our guide on how to grow watermelon before you commit a small planter to it.

Watering an Elevated Planter

Here’s the catch with standing planters: they dry out faster than anything in the ground. The shallow soil tray, the exposure to wind on all sides, and the free-draining bottom all pull moisture quickly—in summer heat you may water daily. Stick a finger two inches down before watering, and consider mulching the surface with straw or shredded bark to slow evaporation. If you’re growing thirsty crops like tomatoes, this is worth planning for—the same watering discipline applies whether you’re in this planter or following our guide to growing tomatoes in pots. A simple drip line on a timer takes the daily chore off your plate entirely.

Cost Breakdown

Real-world ranges for the 2×4-ft standing planter, varying by region and wood grade:

• Cedar 1×6 boards (4 @ 8 ft): $55–$85
• 2x4s for legs and rails (3 @ 8 ft): $15–$30
• 1×4 slats (3 @ 8 ft): $12–$25
• Exterior screws (two boxes): $12–$20
• Landscape fabric: $8–$15
• Raised-bed mix (3–4 bags): $25–$45
• Optional casters (set of 4): $20–$40

All in, a DIY build runs about $90–$130 in lumber and hardware (plus soil), and a simple small box can come in nearer $40 if you scale down or use fir for more of the structure. Compare that to retail kits, which run roughly $60–$300 depending on size and material—the small flat-pack ones are cheap but flimsy, and the nice cedar elevated kits land at the top of that range. Building it yourself gets you better wood and joinery for less, and you control the dimensions.

Permits, HOA, and Placement

Good news—a planter box almost never needs a building permit. It’s furniture, not a structure. The exceptions are rare: very large permanent raised beds in some jurisdictions, or anything attached to the house. What’s more likely to bite you is an HOA. Some associations have rules about what’s visible from the street, container heights, or where you can place things on a front patio, so skim your covenants before you build a row of them out front. Backyards are generally fine.

For placement, the main rules are practical: keep wood off siding and away from spots that stay constantly wet (don’t park it in a low spot that puddles), give it six-plus hours of sun for most vegetables, and put it where you can reach a hose. For more patio and outdoor-living projects, browse the Outdoor Living section.

The Ground-Level Raised Bed Variant

Want the simpler, higher-volume version? Build a bottomless 4×4-ft frame, 12 inches tall, and set it directly on soil. Use cedar 2x6s—two rows high gets you 11 inches of wall. Cut eight boards to 48 in, stack two high on each side, and join the corners to four 11-in 4×4 posts or 2×4 cleats with 3-inch exterior screws. There are no legs, no slats, no liner needed (though fabric on the ground underneath suppresses weeds). Set it level, fill it, and plant. Soil volume for a 4x4x1-ft bed is 16 cubic feet—about eight to eleven bags of mix, or far cheaper if you buy bulk raised-bed soil by the cubic yard. It’s the better choice for root crops, sprawling plants, and anyone who wants maximum growing space for minimum carpentry.

Featured project by Gensou Aquascaping