Raised Beds

These are a great asset if you have poorly drained soil that does not perform well. You can replace it with a bed of good quality fertile soil which will drain well and will appeal to those gardeners who find bending more of a challenge than it used to be!

Construction  - Raised beds can be built with a variety of materials, including brick, stone or wood. Brick and stone structures are robust, but are not easy to build and cannot be relocated should you decide on garden redesign. Wood, however, makes excellent raised beds. Recycled wood, which includes railway sleepers and scaffolding planks can be used but may contain preservatives which are carcinogenic. Polythene can be used to line the sides of the bed and separate the soil from the wood. A better option is to use new wood which will not have this problem as modern preservatives are quite safe. New wood construction will provide an attractive feature in your garden.

Dimensions of the beds are important. Everything needs to be within arm’s reach to avoid standing on the soil and compacting it. This limits the maximum width to about 1.2 metres. Paths between beds need to be at least 30 cms wide for pedestrian access and 45 cms for a wheelbarrow.

The height of the bed is important and depends on how you intend to access it, whether standing, sitting or from a wheelchair.

Standing          900mm – 1000mm

Sitting              690mm – 760mm

Wheelchair      615mm

 

Before building the bed, remove any turf from the area of the bed and break up the underlying soil to one spade depth to allow drainage. After the bed has been completed it should be filled with a good quality soil which will drain freely. You may have such material available, if not you should purchase a good quality screened soil from a reputable supplier.  Ideally the soil should comply with BS 3882: 2007. It can be purchased already blended with organic matter, or suitable material can be dug in later. We would recommend shredded horse manure or mushroom compost. The advantage of mushroom compost is that it has been steam sterilised by the mushroom grower, so will contain no pests, weed seed or diseases which would otherwise affect your plants.

If you have room for several raised beds, you will be able to rotate your crops from one season to another. This will help control disease and improve soil fertility. Rotation of legumes (which fix nitrogen), brassicas (which tend to suffer from disease such as club root) and root crops will allow you to make the most of the nutrients, which are available.  As well as good drainage, the soil in a raised bed will warm up more quickly helping to achieve early crops of salads and vegetables.