Planting into raised beds is a great way of growing different plants, fruits and vegetables in your garden. By doing so, you will benefit from improved drainage, increased soil temperature and have the option to use the optimum soil type to improve plant growth.
Before starting to construct your raised beds consider what you want to grow in them, this will affect amongst other things the depth and type of soil required. Most gardeners start the construction of a new raised bed in winter as long as the soil isn’t wet or frozen, or late summer when the temperatures are lower.
Step : 1
Decide the size and position of your raised bed. Make sure that there is room to access both sides without needing to walk over the soil and damage your plants. The minimum depth for raised beds is 20cm (8in) however some plants need 45-60cm (18-24in). Most root vegetables need around 60cm (24in) of soil depth to root deeply. If you plan to build on a hard surface make sure that a depth of at least 40cm (16in) is allowed for. The width and length of the raised bed can be whatever you require.
Top Tip: build the bed so the entire area of soil is within easy arm’s reach!
Step : 3
Choose your material. Perhaps railway sleepers, old scaffolding boards, bricks, natural stone, logs, cement bricks or plastic? Timber is cheap but doesn’t have longevity, whereas sleepers are expensive and hard to work with but last much longer. Next add retaining stakes to each corner of the raised bed (except for masonry beds). We suggest using 5cm timber stakes at every corner sunk at least 30cm into the soil.
Top tip: If using wood, check it hasn’t been treated with toxic preservatives – if this is the case, just line the inside of your wood frame with polythene sheeting to prevent toxins leaching into the soil. Most modern wood treatments are normally safe.
Step : 5
Now to add the topsoil. Use good quality topsoil such as a mixture enriched with fertiliser and compost. Make sure to compact the soil with a spade as you fill up. Add the soil so it’s level with the top of the frame. The soil will eventually drop as it settles.
Top tip: if your raised bed is greater than 50cm (20in) in depth, first remove the existing topsoil and replace with some rubble such as broken bricks and sand for good drainage.
Top tip: after a year top up the soil to keep the depth and to give a nutrient boost for optimum growing.