There are major advantages to using raised beds to grow vegetables if the soil in your garden is poor. Obviously, you get to fill the bed with soil that is suitable for vegetable growing, but also soil drainage is improved and the soil warms up faster in Spring, giving you a head start on the growing season. In addition, a well designed planting plan can increase your productivity and you can enjoy better harvests.

One of the most common raised bed designs is an edged raised bed, produced by constructing a frame from materials such as timber, plastic or brick (see Figure 1). When planning, you should give consideration to how you will access the centre of the bed. If you make the bed too wide, you may be unable to reach plants in the centre. A sturdy construction may allow you to place planks of wood as walkways, but it is easiest to simply reduce the width of your construct so that you can reach the plants from the side. The bed can be as little as 4 ft × 4ft and should raise the soil between 6 and 12 inches. The material you use depends to some extent on your budget. Pine lumber if fine but is less durable and will need replacing quicker than a more expensive timber, like cedar. Be careful that any timber you use has not been treated with any toxic chemicals like creosote as they may leach into your plants. If you are unsure about the history of the material then you should line the inside of the bed with a sheet of polyethylene to be on the safe side.

To construct a wooden frame, simply cut the wood to the desired size and secure the corners with screws, corner brackets or by nailing in wooden support posts (see Figure 2). To reduce weeds in your raised bed, you may wish to lay a piece of weed mat, pieces of cardboard or a thick layer of newspaper in the footprint of the bed and then position the frame over the top.

One of our users, David Goodman, recommends placing large chunks of wood at the bottom of your bed which will store water as they decompose. He has a great gardening blog and there is some excellent information and images that describe how to fill your raised bed (http://www.floridasurvivalgardening.c...). I have tried to summarize in Figure 3.

After all of this, you are finally ready to plant! A good planting plan is key to maximizing the productivity of your bed. Planting in a raised bed is different from elsewhere in the garden as you should aim to concentrate on planting in blocks, rather than row and also practice succession planting (see https://www.plantvillage.com/posts/251) to reuse space when it becomes available. Be aware of how much space specific plants need. You can use square foot gardening technique - divide your bed into square foot sections. You can make planting easier by marking out the sections with string. There are many plans you can follow for planting, an example is provided in Figure 4. This plan represents how many of each plant type can be planted per square foot of bed (i.e. 1 squash plant requires 2 square feet).

Finally, always remember you can use vertical space too by positioning trellises for squash or cucumber to vine around.