Garden & Home Reviews is reader-supported. We earn affiliate commissions from qualifying purchases — how this works.

How to Build a Planter Box

Home/Resources/Power Tools & Workshop/Build a Planter Box
PA
Written & researched by Priya Anand DIY & Tools Editor
Updated August 2026
Wide view of a person drilling into a timber board on a workbench, sawdust in the air, in warm late-afternoon light

Affiliate Disclosure

Some links on this page are affiliate links. As an Amazon Associate, we earn from qualifying purchases — at no extra cost to you. We do not buy, test, or physically handle the products we cover; our rankings come from aggregated owner reviews, ratings and expert consensus. Commissions never change our verdicts. How we rank · full disclosure.

A planter box is a quick, forgiving build that upgrades any porch, patio, or garden, and it’s ideal for a first outdoor woodworking project. A cedar box costs 30 to 70 dollars in lumber and takes an afternoon with a saw and a drill. No permit, nothing structural. The details that decide whether it thrives or rots are all about water: rot-resistant wood, generous drainage holes, a wall liner, and feet to raise it off the ground. Get the drainage right and even simple screwed corners will hold up for years.

How to Build a Planter Box (The Home Depot)

Tools and materials

Golden-hour view of a person drilling into a timber board on a workbench, sawdust in the air

Step 1: Size it to the plants

Decide what you’ll grow and set the depth accordingly: 6 to 8 inches for herbs and lettuce, 10 to 12 inches for most vegetables, 12 to 18 inches for deep-rooted crops. Keep the width to about 2 feet if you’ll reach from one side. Cut the four sides, a bottom, and any corner posts to your dimensions from rot-resistant wood.

Step 2: Assemble the box

Screw the four sides together at the corners — either directly, or into 2x2 corner posts for extra strength and a cleaner look. Drill pilot holes so the screws don’t split the wood near the ends. Use exterior-rated screws that won’t rust and streak the wood. Check the box is square as you fasten.

Over-the-shoulder view of a person drilling into a timber board on a workbench, sawdust in the air, in soft overcast light

Step 3: Add the bottom and drainage

Fit the bottom board(s) and drill several 1/2-inch drainage holes across it. Leave small gaps between multiple bottom boards for extra drainage if you like. This is the make-or-break step: without drainage, water pools, roots rot, and the wood decays. A planter must be able to shed water freely.

Step 4: Line the walls and add feet

Staple landscape fabric or a perforated liner to the inside walls to keep constantly damp soil off the wood — but never seal over the drainage holes. Then attach feet or cleats to the bottom so the box sits raised off the ground, letting water escape and air circulate underneath. Both steps dramatically extend the box’s life.

Overhead view of a person drilling into a timber board on a workbench, sawdust in the air, in bright midday sun

Step 5: Seal the exterior and plant

Apply a plant-safe exterior sealer or oil to the outside to slow weathering (leave the interior unsealed or use a safe product). Let it dry, fill with a quality potting mix, and plant. Re-oil the exterior every year or two, and the box will look good and resist rot for many seasons.

Where to go next

Building for the yard? A birdhouse and a wooden bench use the same outdoor-wood skills, and every build is easier on a workbench. It all lives under the power tools and workshop hub.

We never buy or physically test the tools we rank — our picks come from aggregated owner reviews and expert consensus, explained on how we rank.

Straight Answers

Frequently Asked

What is the best wood for a planter box?

Naturally rot-resistant woods are best: cedar and redwood are the top choices because they resist decay and insects without chemicals, which matters when the wood stays damp and holds soil near plants. Cypress is another good option. Pine is cheap but rots within a few years unless sealed and lined. Pressure-treated lumber lasts a long time and modern treatments are considered safe for garden beds by many sources, but some gardeners avoid it for edible crops — line it if you use it for vegetables. For a lasting, worry-free box, cedar is the go-to.

Does a planter box need drainage holes?

Yes, always — drainage is the single most important feature. Without holes, water collects in the bottom, roots sit in standing water and rot, and the wood decays fast. Drill several 1/2-inch drainage holes across the bottom, and raise the box off the ground on feet or cleats so water can escape and air can circulate underneath. A layer of landscape fabric over the holes keeps soil in while letting water out. A planter that can't drain kills plants and destroys itself.

Should you line a wooden planter box?

Lining helps the box last much longer by keeping constantly damp soil off the wood. Staple landscape fabric or a perforated plastic liner to the inside walls (not sealing the drainage holes), leaving the bottom able to drain. The liner slows rot and, on pine or treated wood, adds a barrier between the soil and the lumber. Don't use a fully sealed, non-draining liner — that traps water and causes the exact rot you're trying to prevent. The liner should keep soil off the walls while water still exits the bottom.

How deep should a planter box be?

Match depth to the plants: 6 to 8 inches is enough for herbs, lettuce, and shallow-rooted flowers; 10 to 12 inches suits most vegetables and perennials; and deep-rooted crops like tomatoes or root vegetables want 12 to 18 inches or more. Deeper boxes also dry out more slowly, which is easier on the plants and on you. Size the footprint to the space and to how far you can comfortably reach in — about 2 feet is a good maximum width if you can only reach from one side.

How do you make a planter box last longer?

Use rot-resistant wood, ensure excellent drainage, line the interior walls, raise the box off the ground on feet, and apply a food-safe or plant-safe exterior sealer or oil to the outside (leave the interior unsealed or use a safe product). Keeping the wood able to dry between waterings is the biggest factor — a box that stays soggy rots in a couple of seasons, while a well-drained, lined cedar box lasts a decade or more. Empty and re-oil the exterior every year or two to extend its life further.