Raised garden beds are essentially a box or walled area that you place soil into to raise the level of the garden bed. They are extremely useful additions in the garden, especially if the soil quality is poor in your area. Raised garden beds are easier to access, due to their increased height off the ground, and allow wheelchair assisted individuals to garden comfortably. Railway sleepers offer a very sturdy and durable material for raised garden beds. They are relatively cheap, available at most lumber yards, and look very rustic in the garden.
Lay four sleepers on the ground in a square in the area where you want to place the raised beds. Make the corners of the sleepers abut one another in an interlocking pattern so the sleepers make a complete square. Only one end of each sleeper will be visible, the others will be against the next sleeper.
Hammer in two tree stakes equal distance apart on each side of the first layer of railway sleepers (two on the inside and two on the outside). The tree stakes should extend vertically with enough length to go up the sides of the entire stack of railways sleepers. For three layers of sleepers, the stakes should extend approximately 75 cm (30 inches).
Place the remaining railway sleepers on top of the initial layer alternating the way the ends interlock to give the walls strength. There should be four walls, three sleepers high, that form a large, square raised garden bed.
Hammer any tree stakes that remain above the sleepers down into the ground so they are flush with the top sleepers. Most people prefer to leave the rustic look of the railway sleepers as they are, but a lick of paint or natural oil or resin-based varnish won't go astray. Avoid polyurethane varnishes, as they deteriorate faster in outdoor settings with exposure to UV.
Fill the garden bed with potting mix, until it is about 2.5 cm (1 inch) from the top of the sleeper wall. This large raised garden bed is suitable for growing herbs, vegetables, flowers, or even small trees. Planting can begin right away.
It can help to line the inside walls of the raised bed with a poly sheet prior to filling with soil—this protects your plants from any residual chemical leaching from lumber treatment that the sleepers may have gone through. Have the lumber yard cut the sleepers to size if you want a different sized garden bed than the standard sleeper size of roughly 23 by 18 cm (9 by 7 inches) at about 2 metres (7 foot) long, as this makes quite a large garden bed.
You may need a helper for building a raised bed out of railway sleepers, as they are very heavy. Wear heavy-duty footwear, such as steel-capped boots when moving railways sleepers to protect your toes in case of accidents.