Q What are the best materials for building an inexpensive raised bed?

A When Which? Gardening magazine trialled different materials for making raised beds, we found that the best were sleepers and scaffold boards.

Q What are the pros and cons of using sleepers for raised beds?

A The pros are that the 1.2m slimline sleepers we used cost just £7.49 each from a local builders’ merchants. As they were already sold in the length we required, we didn’t need to cut them down to size. They were solid enough to screw together without needing a corner post. This reduced the installation time.
The sleepers were easy to screw together and created a solid bed with a good depth of soil to plant in to. The construction was solid and the sleepers showed no signs of rot, warping or soil seepage, even after 18 months. The yield of crops was satisfactory.

The cons are that you’ll need a long drill bit to create the pilot holes to screw together the sleepers. Wood thickness means the bed takes up slightly more space and also reduces the internal planting area. The bed retained moisture well, but made the soil a bit wet and heavy to dig in spring. Delivery charges for sleepers can be high.

 Caption: Raised beds made of sleepers are relatively quick to construct

Q What are the pros and cons of using scaffold boards for raised beds?

A The pros are that the long length of a standard scaffold board meant that we only had to buy two to cut down for the size of our beds. At 23cm-wide, they were also bigger than most of the other boards we tried. This gave the bed a good depth of soil to plant in to.
The bed looked strong, and when first built it gave the impression it would last for years. The  planks faded a bit in the 18 months they were outside, but the only sign of deterioration was a bit of movement away from the fence post in one corner.
This bed gave the best yield of vegetables, particularly potatoes.

The cons are that the scaffold boards were among the heaviest materials to work with. The reinforcing metal strips taped around the plank ends reduced the visual appeal of the otherwise
chunky and robust-looking beds.
The long length of the boards makes them difficult to get home in a car, so you may need to pay to have them delivered.

Caption: Scaffold boards make durable raised beds