Building Raised Beds for a Courtyard Garden

Why Raised Beds Earn Their Keep in a Courtyard

Most courtyards come with two problems: not much room, and not much choice about the ground you've been given. Very often that ground is compacted clay, riddled with builder's rubble, or shaded by a wall for half the day. Digging it over is thankless work, and in a wet UK winter you'll be standing on soil that holds water like a plugged sink.

Raised beds solve both issues at once. You control the growing medium, so you're no longer at the mercy of what's underneath. You raise the working height, which saves your back and means you can garden sitting on a stool. And the frames themselves give a small space structure, dividing a plain yard into something that looks deliberate rather than improvised.

The trade-off is cost and watering. Raised beds dry out faster than open ground, so if your courtyard is a sun trap, plan for more frequent watering in July and August.

Choosing Timber That Will Last

For a courtyard you want timber that looks good as well as survives. Tanalised softwood is the sensible budget choice and will give you eight to twelve years if the boards are thick enough. Oak or sweet chestnut are the premium options: no treatment needed, handsome greying, and they'll outlast most of us. Avoid old railway sleepers unless you know their history, and skip pallet wood for anything deeper than 15cm, as it simply isn't strong enough to hold wet compost.

Board thickness matters more than people expect. Aim for at least 38mm, ideally 44mm. Thinner boards bow outwards once the compost swells in winter.

• Height: 25–30cm for salads, herbs and most veg; 40–45cm where you want to sit while working or grow deep-rooted carrots and parsnips.
• Width: 90–120cm maximum, so you can reach the middle from either side without stepping on the soil.
• Length: anything you like, but 1.2–1.8m sections are easier to move and replace.
• Fixings: galvanised screws or stainless steel, not plain steel, which will rust through in two seasons.

Setting Out the Frames in a Tight Space

Start by watching where the sun falls. In a courtyard, the difference between the bed against the south-facing wall and the one in the corner can be three hours of growing light. Put your tallest crops and your sun-hungry tomatoes and courgettes where the light lingers longest.

Mark the footprint with string or a hose before you cut anything. Leave at least 60cm between beds for a path, and 75cm if you want a wheelbarrow to pass. If space is desperately tight, consider one L-shaped bed wrapped around the corner rather than two small rectangles, which wastes room on extra edges and extra paths.

On solid paving, don't sit the timber directly on the slabs. Bed it on a thin layer of sharp sand or slip a couple of plastic shims underneath so water can drain away and air can move. On soil, skim off the top 5cm of turf and loosen the ground beneath with a fork. You don't need to dig deeply, but breaking up that compacted layer helps enormously with drainage.

Check for level as you go. A bed that's 2cm out across 1.5m doesn't sound like much until it's full of wet compost and one corner is permanently waterlogged.

Filling the Beds Without Breaking the Bank

Filling raised beds with bagged compost alone is expensive, and in a courtyard you may not have anywhere to store bulk deliveries. The trick is to fill the bottom third with something free and coarse, then top it with good growing medium.

• Base layer: broken-up rubble, old bricks, or logs and prunings from your own garden. This improves drainage and reduces the volume you need to buy.
• Middle layer: rough garden compost, well-rotted manure, or a mix of both. If you're on clay soil nearby, this is the moment to dig some in.
• Top 20cm: a proper loam-based or peat-free multipurpose compost, sieved if you're sowing directly.

Leave the fill about 3cm below the rim so you can water without it running straight off, and so mulch doesn't spill over the edge.

Gravel Paths: The Finishing Move

Gravel is what turns a collection of boxes into a garden. It looks tidy, drains instantly, and is far cheaper than paving. Use a 10mm pea gravel or a 14–20mm angular gravel in a warm buff or grey.

Lay it properly and it won't migrate into your beds. Excavate about 6cm, put down a weed-suppressing membrane across the whole path, then spread the gravel to 4cm deep. On top of existing paving you can skip the excavation but still use the membrane, held in place with a few dabs of outdoor adhesive.

Run the gravel right up to the timber, or leave a 5cm gap and plant thyme, alpine strawberries or creeping camomile. In a small courtyard, that soft green edge makes an enormous difference.

Keeping the Beds Productive

Raised beds warm up faster in spring, which is a real advantage in a cold, enclosed yard. You can reliably start salads and radishes three or four weeks earlier than in open ground, and hardy winter crops such as kale and leeks will sit happily through most of what a British winter throws at them.

Refresh the top 5cm of compost each spring, rotate your crops between beds to keep pests guessing, and water in the early morning during hot spells so the moisture soaks in rather than evaporating. A simple drip line on a timer, run under the mulch, will save you a surprising amount of time.

Treat the whole thing as a long project rather than a single weekend's work. Build one bed, plant it, see how the light moves through the year, then add the next. Courtyard gardens reward patience far more than they reward haste.