Gardening in Raised Beds

If you’re short on space in your garden, or are having particular troubles maintaining a large vegetable patch then building a raised bed could be the answer to your problems. By using a raised bed you can grow more plants in a smaller space, save your back a bit of work and economise your gardening processes.

You’ll have a greater amount of control over the soil that you grow in, so you’ll be able to fine-tune your pH level and quality of compost without interference from the earth you already have. As your vegetables will be at a raised level, isolated from the earth, you’ll also spend less time worrying about knotweed control and pests, saving you time and expenses on prevention and treatment.

Building your own raised bed is a simpler job than you might think, however you’ll need a day to gather the necessary materials and get it built. The RHS recommend building beds that are wider than 1.5m so that you’ll be able to reach into the bed from each side without crushing your produce. If you’re building multiple beds then they also recommend leaving a width of between 30-45cm between each bed. Longer vegetable raised beds should also run from north to south to grant even sunlight levels to all of your plants.

What materials you choose to build your raised bed with will depend on your budget, manpower and space. Stone is an expensive material that also requires skilled labour to use, but it’s attractive and very long lasting. Brick is similarly strong but will also require a skilled hand employ. Timber is by far the most commonly used material, it’s relatively cheap also very versatile.

Unfortunately, unless you purchase high-quality wood, you may find that your bed is compromised within a few years. Railway sleepers and paving slabs can also be used to build your bed, these will certainly stand the test of time but are also very heavy. If you’re unsure as to whether a raised bed is the right choice for you then you can purchase a DIY raised bed kit from many good garden manufacturer – you can pick one up for around £30 and many have a structural guarantee of around 3 years.

Once you have constructed the frame of your raised bed you will need to decide how you are planning on filling it. If you are happy with the quality of the soil in your garden, in terms of drainage and pH level then you can simply load your raised bed with the compost/soil mix of your choice. If you’ve been saddled with heavy clay or are worried that the pH level of your garden will interfere with your raised bed then you’ll need to line your bed.

If you struggle with drainage issues then you should pour an 8cm layer of drainage material (such as coarse gravel or stones) into your bed first, followed by a layer of geotextile membrane that should provide your bed with enough drainage. If your bed is deeper than 50cm then the RHS recommends removing the topsoil and replacing it with rubble or subsoil. The topsoil can then be mixed with compost or manure in layers in order to provide a natural setting for your vegetables. Once you’ve filled your raised bed you should allow the soil to settle for at least 2 weeks before planting.

When your bed is ready for plants the fun can begin! You’ll get the most out of your new raised bed by efficiently planning before you set about planting anything. Some things to consider are:

  • Using a cold frame or tunnel system in order to prolong your growing season.
  • ‘Intercropping’ plants close to make the most of space and conserve moisture.
  • Intercrop plants that work well together such as heavy feeders (cabbage) with light feeders (carrots).
  • Growing vertically to maximise your bed’s potential, plants like cucumbers, tomatoes and even melons can flourish this way but may need extra care.

Of course, there are a few drawbacks to growing vegetables in a raised garden bed. Moisture is likely to drain a lot quicker (the bed is essentially one large pot which doesn’t have access to the earth’s moisture) and will require you to water it much more frequently. Finally, although the chance of infestation from pests, weeds and diseases is lower when planting in a raised bed, if your bed does get infected you might find that your entire crop is effected – something worth considering before initiating this plan.