How to build a raised garden bed using corrugated sheets
When Bunnings Workshop member Phil_70 considered building a raised garden bed using corrugated sheets, he wondered how to make sure it doesn't collapse under the weight of the soil. Experienced member Adam Woodhams reckoned the "easiest and most cost effective way is to use Treated Pine sleepers (or recycled railway sleepers) as uprights. You'd just run a row of them then drop your sheet in behind and use roofing Tek-screws to fix the sheets to the posts."
"You'd likely want your posts at about 1200mm spacings, maybe a little less. Not sure of the load that the sheets would take so maybe even consider 1m centres. Like any retaining wall, because that's basically what you are building, you'll want to make sure that the uprights are well fixed off to resist tipping. So say your bed wall will be 900mm high I'd be sinking posts into the ground around 500mm and then concreting them in place. Different soils change this though. If you've a heavy clay you don't need to go as deep."
Step-by-step guides to building a raised garden bed