A raised garden bed is one of the most satisfying weekend projects you can do. It’s simple enough for a total beginner, costs surprisingly little, and you’ll be growing vegetables in it within a fortnight. Plus, once you’ve built one, you’ll almost certainly build three more — they’re that useful.
This guide covers how to build a raised garden bed from scratch for under £100, using basic tools and materials from any builders’ merchant or timber yard. No fancy joinery, no expensive hardware — just a solid, practical bed that’ll last years.
Why Raised Beds Are Worth the Effort
If you’ve got decent soil and a flat garden, you might wonder why you’d bother raising it. Fair question. Here’s why raised beds are genuinely worth it:
- Better soil control — you fill them with exactly the mix you want, regardless of what’s underneath. Heavy clay soil? Doesn’t matter.
- Better drainage — raised beds drain faster than ground-level plots, which is a huge advantage in the UK’s wet climate.
- Easier on your back — even a 30cm-high bed reduces bending significantly. Build them 60cm high and you can garden from a chair.
- Fewer weeds — a fresh fill of compost and topsoil has far fewer weed seeds than established garden soil.
- Warmer soil in spring — raised soil warms up faster, giving you a head start on the growing season by 2-3 weeks.
- Defined growing areas — they look tidy, keep paths clear, and make crop rotation simple.
Choosing Your Wood (and Why Treated Timber Is Fine)
There’s a lot of debate online about what timber to use. Let me simplify it:
| Timber Type | Lifespan in Ground Contact | Cost (for a 1.2m × 2.4m bed) | Verdict |
|---|---|---|---|
| Untreated softwood (pine/spruce) | 2-4 years | £25-40 | Cheap, but rots quickly. Fine for temporary beds. |
| Pressure-treated softwood | 8-15 years | £35-60 | Best value. My recommendation for most builds. |
| Cedar | 10-20 years | £80-150+ | Naturally rot-resistant. Beautiful but expensive in the UK. |
| Larch/Douglas fir | 8-15 years | £50-80 | Good middle ground — naturally durable, looks great. |
| Railway sleepers | 20+ years | £15-30 each (reclaimed) | Heavy, characterful, but check for creosote if reclaimed. |
The treated timber question: Modern pressure-treated timber (tanalised) uses copper-based preservatives, not the old arsenic-based CCA treatment that was phased out years ago. It’s approved for use in garden beds across Europe. I’ve used it for all my beds, and every kitchen garden I know of uses it. If you’re still concerned, line the inside with landscape fabric before filling.
Cedar vs Pine vs Treated — What I’ve Used
[PERSONAL EXPERIENCE — Adam, replace this section with your own story. Prompts to guide you:]
- Which timber have you used for your raised beds?
- How have they held up over time? Any that have rotted?
- Did you try untreated first and regret it?
- Where did you source your timber and what did you pay?
- Photo opportunities: your raised beds at different ages showing how the timber has weathered, close-up of any rot or wear
Tools You’ll Need
You don’t need much — this is a properly beginner-friendly build.
- Cordless drill/driver — for driving screws. The most essential tool.
- Saw — a circular saw, mitre saw, or even a hand saw. You only need a few cuts.
- Tape measure
- Pencil
- Spirit level — for checking the frame is level before filling.
- Square — a speed square or combination square for marking cut lines.
Materials and Cut List
This build creates a 1.2m × 2.4m raised bed, 30cm high — a versatile size that’s reachable from both sides and fits standard timber lengths with minimal waste.
| Material | Quantity | Dimensions | Approx. Cost |
|---|---|---|---|
| Treated timber boards | 6 | 150mm × 38mm × 2.4m | £5-8 each = £30-48 |
| Corner posts (treated) | 4 | 75mm × 75mm × 350mm | Cut from one 1.8m post = £8-12 |
| Exterior wood screws | ~40 | 5mm × 65mm | £6-8 (box) |
| Landscape membrane (optional) | 1 piece | 2m × 3m | £5-8 |
Total materials cost: £50-75
For the soil fill (a 1.2m × 2.4m × 0.3m bed needs roughly 0.85 cubic metres):
- Topsoil/compost mix — approximately £30-50 delivered, depending on your area
Grand total: under £100 for a complete, filled raised bed.
Step-by-Step Build Instructions
Step 1 — Cutting the Timber
From your six 2.4-metre boards:
- 4 boards stay at full length (2.4m) — these are the long sides, two per side stacked to give you the 30cm height.
- 2 boards get cut in half to create four 1.2m pieces — these are the short ends, two per end.
For the corner posts, cut your 75mm × 75mm post into four pieces at 300mm long (matching the bed height minus the board thickness at the base).
That’s all the cutting done. Told you it was simple.
Step 2 — Assembling the Frame
- Start with one long side. Lay two 2.4m boards on edge, one on top of the other. Place a corner post inside at each end, flush with the board ends and top. Drive two screws through each board into the corner post — four screws per corner.
- Attach a short end. Stand the assembly up. Hold a 1.2m board against the corner post at one end and screw it in place. Add the second 1.2m board on top. Repeat for the other end.
- Complete the rectangle. Attach the remaining two 2.4m boards to close the frame, screwing into the corner posts at each end.
- Check for square. Measure the diagonals — if they’re equal (or within 5mm), your bed is square. If not, push the longer diagonal gently until they match.
Pro tip: Pre-drill your screw holes. Treated timber is dense, and driving screws near the ends without pre-drilling almost guarantees splitting. A 4mm drill bit for 5mm screws works perfectly.
Step 3 — Lining the Bed (Do You Need To?)
There are two reasons you might line the inside of the bed:
- To separate the soil from the timber — this slows rot and addresses any concerns about treated timber leaching. Use landscape membrane (weed fabric), not plastic sheeting. Plastic traps moisture against the wood and actually accelerates rot.
- To suppress weeds from below — lay cardboard or landscape fabric across the bottom of the bed before filling. Weeds will push through eventually, but it buys you a season or two of reduced weeding.
Lining the sides is optional. Lining the base is worthwhile if you’re placing the bed on existing garden soil or grass.
Step 4 — Filling with the Right Soil Mix
Don’t just fill it with garden soil from elsewhere in the garden. The whole point of a raised bed is controlling your growing medium. The ideal fill is:
- 60% quality topsoil
- 30% compost (garden compost or well-rotted manure)
- 10% perlite or sharp sand — for drainage, especially in clay-heavy areas
Fill the bed to the top — the soil will settle by 5-10% over the first few weeks. Water it thoroughly after filling and top up any low spots before planting.
Budget tip: If you have a compost bin that’s been working for a year or more, use your own compost as the 30%. Free, nutrient-rich, and exactly what your plants want.
Where to Place Your Raised Bed
Location matters more than most people realise:
- Sunlight — most vegetables need at least 6 hours of direct sun per day. 8+ hours is ideal. South-facing or south-west-facing is best in the UK.
- Level ground — a slightly unlevel bed is fine (you can shim it with offcuts), but building on a steep slope creates headaches with soil washing out.
- Water access — you’ll be watering regularly in summer. Being within hose reach makes life much easier.
- Away from large trees — tree roots will invade from below, and the canopy will steal your sunlight.
- Proximity to the kitchen — sounds daft, but beds close to the back door get tended more often. Out of sight, out of mind.
What to Plant First (Beginner-Friendly Picks)
If this is your first bed, start with things that are hard to kill and rewarding to harvest:
- Salad leaves (lettuce, rocket, spinach) — fast-growing, cut-and-come-again. You’ll be eating from the bed within 4-6 weeks.
- Radishes — ready in 3-4 weeks. Instant gratification.
- Courgettes — one plant produces more courgettes than you can eat. Plant in late May.
- Runner beans — productive, easy, and the kids love watching them climb. Need a simple cane frame.
- Herbs (parsley, chives, mint) — useful in the kitchen and very forgiving. Plant mint in a pot sunk into the bed, or it’ll take over.
- Potatoes — great for breaking in new soil. The digging at harvest aerates the bed beautifully.
Avoid starting with anything fussy — tomatoes, peppers, and aubergines need consistent warmth and attention that can be discouraging for a first-time grower.
Mistakes I Made with My First Raised Bed
Not measuring corner to corner. when you do this for all 4 corners they should be the exact same value, if they aren’t the bed isn’t square…
the 345 technique really helps here
The Kit I’d Recommend if You Don’t Want to Build from Scratch
If woodworking isn’t your thing and you’d rather just assemble something, there are some excellent pre-cut raised bed kits available. They typically cost £60-120 and come with pre-drilled timber that slots together in about 20 minutes.
The advantages of a kit:
- No cutting required
- All fixings included
- Timber is usually pre-treated
- Consistent quality
The disadvantages:
- More expensive than buying timber directly
- Fixed sizes — you can’t customise dimensions
- Sometimes the timber is thinner than what you’d choose yourself
Whether you build from scratch or buy a kit, the important thing is getting started. A raised bed full of salad leaves and herbs beats a perfect plan that never gets built. And at under £100 all in, it’s one of the cheapest and most rewarding projects you can do in the garden.
