Raised Bed Gardening

The Case for Raised Beds

The raised bed system — growing in defined, permanently made beds that are never walked on — is the most productive, labour-efficient approach to the kitchen garden. The benefits compound over time: soil structure improves because it is never compacted, fertility builds because organic matter is applied to a smaller area, and weeds are easier to manage in a clearly defined space.

Raised beds can be at ground level (simply defined areas never walked on) or built up with boards to create a raised growing surface. Building up is worth doing: it improves drainage, warms faster in spring, is easier to work on, and makes sense on compacted or poor soils.

Dimensions

The critical dimension is width: beds should be no wider than you can comfortably reach to the centre from both sides — typically 1.2m (4 feet). This means you never need to step onto the growing surface. Length is flexible — 2.4m (8 feet) is a common practical choice that allows easy access from the ends.

Paths between beds should be at least 45cm (18 inches) — wide enough to work comfortably, kneel, and manoeuvre a wheelbarrow.

Building the Beds

Boards can be of any rot-resistant timber: oak, larch, Douglas fir, or untreated hardwood. Avoid pressure-treated softwood, as the preservatives may leach into food crops. Railway sleepers are popular but can leach creosote. Recycled scaffolding boards are a practical and economic choice.

Height of 20–30cm (8–12 inches) is usually sufficient. Deeper is not necessary unless you are building over very poor subsoil or hardcore.

Filling and Soil Building

Fill new raised beds with a mixture of topsoil and well-rotted compost. For a bed built over grass or weeds, lay cardboard first to suppress growth — no need to dig. Each autumn, top-dress beds with 5–7cm of compost, leaf mould, or well-rotted manure. This is the only input the system needs.

Intensive Planting

The absence of paths within the growing area means you can plant more densely than traditional row gardening. Following 'equidistant' rather than 'in rows' spacing — spacing plants so each is equidistant from its neighbours — maximises use of space and creates a canopy that suppresses weeds naturally.