Raised garden beds are the cheat code of gardening: better soil, fewer weeds, easier on your back, and they look fantastic. Building a raised garden bed is a genuinely easy weekend project — basic timber, basic tools, and about £30–£50 in materials. Here’s how to do it properly.

Why raised beds work so well

• You control the soil. Fill with quality topsoil and compost instead of fighting whatever’s in your ground (clay, rubble, tree roots).
• Better drainage. Raised soil drains freely — no waterlogged roots.
• Earlier planting. Raised soil warms up faster in spring, extending your season by weeks.
• Fewer weeds. Weed seeds in the surrounding soil don’t migrate up easily, and the defined area is quick to hoe.
• Ergonomics. Less bending. Your back notices the difference immediately.

What you’ll need

• Timber: scaffold boards (the classic — £8–£12 each, 3.9m long) or 150mm x 50mm treated timber. Avoid old railway sleepers (creosote) and untreated softwood (rots in 2–3 years). For a standard 2.4m x 1.2m bed, you need 4 boards cut to length, or 2 full scaffold boards.
• Corner posts: 50mm x 50mm treated timber stakes, or simply screw boards together with long screws.
• Screws: 75–100mm exterior wood screws (£5).
• Weed membrane for the base (£8 for a roll — you’ll use it elsewhere too).
• Cardboard — free weed suppressant (see below).
• Soil: good topsoil mixed 60/40 with compost or well-rotted manure. A 2.4m x 1.2m x 30cm bed needs about 0.85 cubic metres — roughly a bulk bag (£60–£90 delivered) plus compost.
• Tools: saw, drill/driver, tape measure, spirit level — all in the basic toolkit.

How to build a raised garden bed: step by step

1. Choose the position. Most veg needs 6+ hours of sun. Avoid tree roots (they’ll invade) and low spots that flood. Consider access — you’ll carry watering cans and harvests.
2. Size it right. Maximum 1.2m wide (so you can reach the middle from either side without stepping in), any length you like, 25–40cm deep. Deeper is better for root veg; 30cm suits most things.
3. Prepare the ground. Mow grass short. Lay cardboard directly on the ground inside the footprint — it smothers grass and weeds and rots down within months. No need to dig.
4. Cut the timber. For a 2.4m x 1.2m bed: two 2.4m boards and two 1.2m boards per layer. Most beds are one scaffold board high (22cm) — fine for most growing. Two high (44cm) is luxurious for root veg and bad backs.
5. Assemble the frame. Screw corners together — pre-drill to avoid splitting. Check it’s square (measure diagonals; equal = square) and level.
6. Position and level. Set the frame on the cardboard, check level, pack soil underneath low spots.
7. Line the sides (optional). Staple weed membrane to the inside faces to protect timber from damp soil — extends the boards’ life by years.
8. Fill. Bottom half: rough organic matter (leaves, straw, even logs — hugelkultur style). Top half: your topsoil/compost mix. Water well to settle, then top up — it’ll sink 10–15% in the first weeks.
9. Mulch the surface with 5cm of compost or bark. Plant.

What to grow (first-year winners)

• Foolproof: courgettes, runner beans, lettuce, radishes, spring onions, potatoes, herbs.
• High value: tomatoes, chillies, cut flowers — expensive to buy, easy to grow.
• Avoid first year: carrots in stony soil (they fork), cauliflower (fussy), celery (demanding).
• The salad bed: one bed of cut-and-come-again lettuce, rocket and herbs pays for itself by June.

Maintenance

• Top up annually with 5cm of compost each autumn — soil levels drop as organic matter breaks down.
• Rotate crops — don’t grow the same family in the same bed year after year (prevents disease buildup).
• Check timber yearly; re-treat with linseed oil or wood preserver to extend life. Scaffold boards last 5–8 years; replace as needed.
• Water deeply — raised beds drain well, which means they dry faster in summer. Mulch heavily to retain moisture.

Cost breakdown (one 2.4m x 1.2m bed)

• Timber (2 scaffold boards): £20
• Screws: £5
• Cardboard: free
• Soil (bulk bag, shared across 2 beds): £40
• Compost: £15
• Total: ~£80 for the first bed, ~£40 for each additional (soil is the main cost)

It’s one of the best-value projects in our budget garden guide — productive, attractive, and permanent.

Raised bed watering: the critical detail

Raised beds dry out faster than ground-level soil — the number one reason beginners’ raised beds underperform. The solutions, in order of effectiveness:

• Mulch heavily: 7–10cm of straw, bark or compost on the surface cuts water loss dramatically. The single most effective step.
• Water deeply, not often: a thorough soaking twice a week beats a daily sprinkle. Deep watering encourages deep roots; sprinkling encourages shallow, thirsty ones.
• Water in the morning: less evaporation than midday, and foliage dries before night (reducing slug and disease problems).
• Drip irrigation: a simple seep hose (£15–£25) on a timer (£20) waters the soil, not the leaves, with zero effort. Pays for itself in a month of saved watering time.
• Ollas (unglazed clay pots): buried in the bed and filled with water, they seep moisture slowly to the roots. Ancient technology, remarkably effective, and they look charming.

Companion planting in raised beds

• Carrots + onions: onions confuse carrot fly; carrots confuse onion fly. Plant in alternating rows.
• Tomatoes + basil: the classic pairing — basil may improve tomato flavour, and both love the same conditions.
• Beans + sweetcorn + squash (the “three sisters”): beans fix nitrogen, corn provides support, squash shades the soil. Ancient wisdom that works.
• Marigolds everywhere: French marigolds repel whitefly and aphids. Plant them around the bed edges — pretty and functional.
• Avoid: onions/garlic near beans and peas (they inhibit growth).

Winter growing in raised beds

Raised beds aren’t just for summer. Sow winter salads (lamb’s lettuce, winter purslane, land cress) in September, plant garlic and broad beans in October–November, and cover with fleece in hard frosts. A bed that produces in February feels like magic — and the soil structure improves year-round when it’s planted rather than bare.

The RHS guide to growing in raised beds has crop-by-crop advice once your bed is built — planting distances, rotations and month-by-month jobs.

The takeaway

To build a raised garden bed: screw scaffold boards into a 1.2m-wide frame on cardboard, fill with topsoil and compost, mulch, and plant. One weekend, under £80, and you’ll be harvesting salads within two months. Start with one bed — I’d bet money you’ll build a second by next spring.