The Core Trade-Off
Metal and wood raised beds both get the job done, but they do it differently. Wood is cheaper upfront, easier to work with, and has a natural look that suits most gardens. Metal lasts longer, requires less maintenance, and heats soil faster in spring. Neither is objectively better. The right choice depends on your budget, your climate, how long you want the beds to last, and what matters to you aesthetically. This comparison lays out the practical differences so you can make an informed decision rather than relying on marketing claims from either camp.
Durability and Lifespan
Corrugated steel and galvanised metal beds typically last fifteen to twenty-five years before showing significant deterioration. The zinc coating on galvanised steel protects against rust, and even when it eventually wears through, the steel beneath takes years to corrode fully. Corten steel beds are designed to form a stable rust layer and can last even longer. Cedar and redwood beds, the most rot-resistant timber options, last eight to fifteen years depending on climate and soil contact. Pressure-treated pine is cheaper but raises questions about chemical leaching, especially in edible gardens. Untreated softwood rarely lasts more than four or five years in ground contact.
Cost Breakdown
A basic four-by-eight-foot wood raised bed built from cedar costs roughly sixty to one hundred and twenty pounds in materials, depending on timber thickness and local prices. The same size in corrugated galvanised steel runs one hundred and fifty to three hundred pounds for a kit, or less if you source panels and assemble yourself. However, you need to factor in replacement costs. If a cedar bed lasts ten years and a metal bed lasts twenty, the lifetime cost per year is often similar. Metal beds also hold their resale value better if you move house or redesign your garden, which is worth considering.
Soil Temperature and Growing Performance
Metal beds absorb and conduct heat more readily than wood. In spring, this means soil in a metal bed warms up faster, which can give you a head start on the growing season by a week or two. In hot summer climates, however, that same heat conduction can overheat roots near the bed walls. Planting a buffer of less heat-sensitive crops around the perimeter or insulating the interior with cardboard helps. Wood beds insulate naturally and maintain more stable soil temperatures throughout the day and across seasons. For most temperate climates, both materials grow food equally well once summer arrives.
Aesthetics and Garden Style
This is subjective, but it affects satisfaction with your garden. Wood raised beds suit cottage gardens, traditional plots, and natural-looking spaces. They weather to a silver-grey that blends into most settings. Metal beds have a modern, clean-lined look that works well in contemporary garden designs and urban spaces. Corten steel develops a warm rust patina that some gardeners love and others find untidy. If visual consistency matters to you, consider what else is in your garden. A corrugated metal bed next to a rustic wooden fence can look awkward, just as a rough-sawn timber bed might clash with a sleek patio.
The Practical Verdict
Choose wood if you want low upfront cost, easy DIY construction, and a traditional look. Choose metal if you want longevity, minimal maintenance, and faster spring soil warming. For edible gardens specifically, both are safe choices provided you use untreated or food-safe timber, or galvanised and food-grade metal. Avoid reclaimed materials of unknown origin in either case. Whichever you pick, the soil you fill the bed with and how you manage it will have a far bigger impact on your growing success than the material the walls are made from.