One basic wooden garden planter comes together in an afternoon with simple tools, solid timber, and good drainage for healthy plants.
A wooden garden planter lets you grow herbs, salad leaves, flowers, or even small shrubs in a tidy, raised box that suits almost any space. With a few boards, a drill, and a clear plan, you can build a sturdy planter that looks neat and lasts for years.
Why Build A Wooden Garden Planter
A wooden garden planter gives you control over soil, drainage, and layout without needing to dig up half the yard. Raised sides warm up faster in spring, so seedlings can go out earlier, and the contained shape keeps paths tidy. If your ground is poor, stony, or heavy clay, a planter filled with decent soil turns a tough space into a productive bed.
Timber is easier to work than brick or stone, especially if you have only a basic saw and drill. Boards can be cut to any length, so you can match the planter to a balcony corner, a narrow side return, or a full kitchen garden. When you learn how to make a wooden garden planter once, you can repeat the same method for several beds in different sizes.
Plan Sizes And Materials Before You Start
Good planning saves wasted timber and awkward sawing later. Start by deciding what you want to grow, because root depth guides planter height. Shallow salad crops manage with sides around twenty centimetres tall, while deeper rooted vegetables and shrubs usually do better with thirty to forty five centimetres of depth. Many gardeners pick a width of around one point two metres so they can reach the centre from both sides without stepping onto the soil.
Next, choose wood that lasts outdoors. Popular options include cedar, larch, and pressure treated softwood boards. Modern treated lumber uses copper based preservatives and is widely used for raised beds. If you prefer a barrier, you can line the inside with heavy plastic so soil does not sit directly against the timber. Screws should be corrosion resistant, labelled for exterior use, so fixings do not rust away after a few wet seasons.
Typical Planter Sizes And Timber Shopping List
Use the table below as a starting point when you buy wood. Measurements are approximate and you can adjust lengths to suit your space.
| Planter Size (L × W) | Board Lengths And Quantity | Typical Use |
|---|---|---|
| 60 × 40 cm | 4 × 60 cm, 4 × 40 cm, 4 corner posts | Herbs, salad leaves, balcony rail area |
| 90 × 45 cm | 4 × 90 cm, 4 × 45 cm, 4 corner posts | Cut flowers, lettuce, compact peppers |
| 120 × 60 cm | 4 × 120 cm, 4 × 60 cm, 4 corner posts | Mixed veg bed for small garden |
| 150 × 75 cm | 4 × 150 cm, 4 × 75 cm, 4 corner posts, 1 brace | Root crops, bush tomatoes, beans |
| 180 × 90 cm | 4 × 180 cm, 4 × 90 cm, 4 corner posts, 1–2 braces | Main raised bed, family veg box |
| 240 × 90 cm | 4 × 240 cm, 4 × 90 cm, 4 corner posts, 2 braces | Large kitchen garden planter |
| Square 90 × 90 cm | 8 × 90 cm, 4 corner posts | Feature planter with shrub and underplanting |
Tools And Materials For How To Make A Wooden Garden Planter
You do not need a workshop full of gear for this project. A hand saw or circular saw, a drill driver, a square, a tape measure, and a pencil will handle almost every task. A clamp or two helps hold corners square while you screw them together, and a sanding block smooths sharp edges so they do not snag clothing.
For materials, gather your timber boards, corrosion resistant wood screws, and a few short offcuts or stakes to use as internal corner posts. A strip of landscaping fabric or thick plastic liner protects soil from washing out and slows wood decay. Have coarse gravel or broken pot pieces ready for the base layer, then a mix of topsoil and compost for filling. Wear gloves and eye protection while cutting or drilling, especially when you work with treated boards.
Marking Out The Site And Preparing The Base
Before you make any cuts, mark where the planter will sit. Lay out a rough rectangle on the ground with a tape measure and pegs, checking that diagonal measurements match so the corners stay square. A level surface helps water drain evenly, so scrape away thick turf, roots, and stones, and rake the area until it feels flat underfoot.
If you are placing the planter on soil, loosen the top few centimetres with a fork to help roots move down into the ground. On a patio or balcony, check that surface water has somewhere to run and that the weight of a filled planter will not stress the structure. Many people add a thin layer of coarse gravel at the base to keep drainage holes clear and stop soil from sitting in puddles after heavy rain.
Step By Step: How To Make A Wooden Garden Planter Box
Step 1: Cut Side Boards And Corner Posts
Measure and cut the long and short side boards to your planned lengths. For a simple rectangular planter, you need two long sides and two short ends. Cut four corner posts from thicker offcuts; these posts sit inside each corner and take the screws, which keeps the outside faces neat and helps stop the boards from splitting.
Step 2: Assemble The Long Sides
Lay a corner post on a flat surface, hold one long board against it so the edges are flush, and drill pilot holes before driving screws through the board into the post. Add a second screw near the other end of the board for strength. Repeat at the opposite end with another post, then build the second long side in the same way. Check that the posts sit square to the boards so your planter will stand straight.
Step 3: Attach The Short Ends
Stand the two long sides upright, posts facing inward, and position a short end board between them at one end. Use a clamp if you have one, or ask a helper to hold the board while you drill pilot holes and drive screws through the short board into each corner post. When the first level is fixed, add the second row of boards above it to build the full height of the planter.
Step 4: Add Mid Span Bracing If Needed
If your planter is longer than about one point eight metres, add a brace across the middle to stop the boards from bowing under the weight of damp soil. Cut a short piece of timber to span between the two long sides, then screw it into the inside face of each board. This simple brace keeps the planter square and gives you a handy grip when you shift the empty frame.
Step 5: Check For Square And Fix In Place
Measure the diagonals of the finished frame once more. If the two diagonal measurements match, the planter is square; if one is longer, push the longer corner in slightly and recheck until the frame sits evenly. Set the frame on its prepared base and, if you are on soil, hammer a couple of stakes into the ground inside the corners or along the sides, then screw the frame to these stakes so wind or stray feet cannot shift it.
Lining, Drainage, And Soil Mix
Wood touches damp soil for much of the year in a garden planter, so anything that reduces constant moisture against the boards helps them last longer. Many gardeners staple heavy plastic sheeting or strong landscaping fabric to the inside walls. Stop the liner a few centimetres below the rim so the top edge of the timber can dry between showers, and punch or drill holes through the liner near the base so water can drain freely.
Planters need a free draining base rather than a solid pan of soil. Spread a shallow layer of coarse gravel, stones, or broken pots, then add your soil mix. Guidance from the Royal Horticultural Society notes that a depth of around thirty centimetres suits shallow rooted crops, while deeper fruit bushes and shrubs benefit from forty five centimetres or more of soil depth, so match your planter height to what you want to grow.
A simple mix of good topsoil blended with garden compost or well rotted manure gives structure and nutrients. Many growers prefer beds filled mainly with soil, since pure compost can slump as it breaks down. If you are short of topsoil, you can mix in bagged topsoil and composted bark to bulk out the volume while keeping the texture open.
| Planter Use | Soil Mix Ratio | Notes |
|---|---|---|
| Leafy greens and herbs | 60% topsoil, 40% garden compost | Loose surface, holds moisture but still drains |
| Root crops | 70% sieved topsoil, 30% sand or grit | Fewer stones, helps carrots and parsnips grow straight |
| Fruit bushes | 70% topsoil, 20% compost, 10% well rotted manure | Rich but firm mix for long term planting |
| Mixed veg bed | 60% topsoil, 30% compost, 10% manure | Balanced mix for seasonal crops |
| Herb planter | 50% topsoil, 30% compost, 20% grit | Free draining blend for Mediterranean herbs |
| Flower display | 50% topsoil, 50% multi purpose compost | Good for bedding plants and container annuals |
Safety Notes On Timber Treatment
Modern pressure treated lumber sold for domestic projects is designed to stand outdoors for years without rotting. Treatment formulas moved away from older arsenic based products, and research from extension services suggests only minor leaching of copper into soil near the boards. Trials reported by University of Maryland Extension found no increase in copper levels within crops grown in raised beds made from current treated timber.
If you still prefer extra caution when you make a wooden garden planter, you have several simple options. You can line the inside of the boards with a heavy plastic membrane before filling, paint or stain the outside faces so hands do not touch raw timber, or choose naturally durable wood such as cedar, larch, or oak. Wear gloves and a dust mask when cutting or sanding treated boards, and never burn offcuts, since smoke from any treated wood is unsafe to breathe.
Planting And Spacing Inside The Planter
Once the planter is built and filled, rake the surface level and water the soil so it settles. Plan your layout before pressing in seedlings or seed rows. Group taller plants towards the back or centre, and keep sun loving herbs or flowers where they will not be shaded by broad leaves. Leave gaps between rows so air can move freely; crowded plants stay damp for longer after rain, which encourages disease.
Ongoing Care To Keep Your Planter In Good Shape
A wooden garden planter needs only modest care each season to stay sound. Check the corners and screws each spring and tighten any that have loosened as the timber swelled and shrank. Brush off soil that builds up on the outside faces, since damp soil against the boards speeds decay. Every few years, top up the soil level with a fresh layer of compost so roots still have room to grow and nutrients stay balanced. That keeps routine care manageable.
During dry spells, planters dry out faster than ground beds, so regular watering keeps crops alive and productive. A drip hose or soaker pipe laid along the rows gives steady moisture with less waste than overhead sprinkling. Mulching the surface with straw, grass clippings, or bark chips slows evaporation and cuts down on weeding time. With these habits in place, your planter will stay solid and useful for many seasons after that first satisfying build.