HOW TO BUILD A RAISED BED WITH SLEEPERS

Building raised beds is a great way to add more growing space to your garden and you can quickly get growing fruit, vegetables, cut flowers or even small trees and shrubs.

Before you add raised beds to your garden, there are a few things to consider:

• Orientation - most fruit, vegetables and cut flowers need full sun, so have beds south-facing away from the shade of overhanging trees.
• Size - long runs of beds can be inconvenient to manage, so opt for multiple smaller beds. Widths of less than 1.5m (5ft) should allow you to easily reach the centre without having to stand on the soil.
• Depth - 30cm (1ft) is deep enough for dwarf bulbs, salad leaves and strawberries, but most plants, especially fruit bushes, shrubs and small trees, need 45cm (18in) or more.
• Pathways - aim to make paths between beds at least 45cm (18in) wide to accommodate a wheelbarrow.

Timber is the most popular material for constructing raised beds and is very versatile. Pressure-treated softwood sleepers are an attractive and economical alternative to hardwoods like oak, and will last for many years.

Untreated wood, like recycled pallets and scaffold boards, have a shorter life than treated wood, but can be painted with a preservative to extend its lifespan - just remember to line the inside of the wood with old compost bags or other recycled plastic sheeting to prevent leaching into the soil.

You can build raised beds at any time of year, but most gardeners prefer to do it in winter when they have more time - just avoid working the soil if it is very wet or frozen. If your garden has heavy soil and waterlogging is a problem, it's best to build your beds in late summer when the ground is drier and more easily cultivated.

BUILDING A RAISED BED

Mark out where your raised bed will be using canes and string, then dig a shallow trench to its exact dimensions, wide enough to accommodate the timbers.

Lay the timbers into the trench and make sure they all align horizontally using a spirit level. Check the levels diagonally between the timbers as well as along their length.

At each corner, drill through the end timber into the sleeper behind, at the top and bottom, to accommodate a couple of long, heavy-duty coach screws. Then screw the timbers together securely.

If you want to add a second layer, put the timbers in place, making sure these overlap the joints below to give the structure extra strength. Screw in place, as previously. Repeat, if necessary, until the bed is the height you require. If using more than one layer, screw vertical batons inside each corner, to secure the layers together.

Lining your raised bed with landscaping fabric, polythene or permeable membrane before adding in soil, is also a popular choice for increased durability. Using heavy duty staples and a staple gun, secure the liner to the sides of the bed before trimming the excess away. If you are planning on planting small trees, plants or shrubs, lining the bed is not necessary.

Lift and remove any turf from the base of shallow beds, and lightly fork over the soil to loosen it.

For beds deeper than 50cm (20in), remove any turf and the underlying topsoil, replacing with rubble or subsoil to ensure good drainage and reduce the quantity of good soil needed to fill the bed.

To fill the beds use a general potting mixture of three parts organic matter (such as garden compost, leafmould or well-rotted manure), two parts sharp sand and seven parts topsoil. For alpines, bulbs and herbs, that like good drainage, double the proportion of sand. For deep beds, add-in any topsoil removed from the base.

Fill the bed to around 5cm (2in) below the rim. Firm down the soil and leave it to settle for a couple of weeks, topping the level up again if necessary. Then you are ready to start sowing or planting.