Raised beds are quite a hot topic at the moment in the gardening world for instant gardening appeal. Raised beds are a speciality of Garden Ninjas, and for good reason, they provide an easy way to garden practically anywhere! You can forget the woes of heavy clay soil or that ugly bed that's compacted and simply build up with raised beds. This guide shows you how to create amazing raised beds.

This raised bed guide will explain exactly when and how to use raised beds for successful gardening. Raised beds can be used in nearly all gardens regardless of the condition, or even absence, of soil. It allows you to build up and choose the soil you need for the plants or vegetables you want to grow. Raised beds are super easy to maintain and can take your garden from bland and boring to incredible. Other than the time taken to make or install them there really aren’t many drawbacks. Raised beds can also be used as a really striking garden design feature too as shown in my Family Garden Transformation installation.

What are raised beds?

Raised beds or raised bed gardening is using a structure that allows planting on top of an existing level. This may mean planting on top of a current garden border, paving terrace, unused areas or structure. It allows you to create a raised area in which to plant. Raised beds bring the height of the gardening area up to a level of your choice.

This reduces the backbreaking complaint that is sometimes made about gardening. This also means that you can avoid having to undertake a large amount of hard landscaping because you don’t need to excavate huge amounts of soil or debris first. You simply build the bed, fill it with soil and you’re good to go!

beginners guide to raised bedsThere’s also no real need to get a builder or construction team round to create raised bed planting in most cases. The hardest part is usually filling them with soil which does require some manpower. You do need to be relatively comfortable with some light DIY, using a hand saw, screwdriver and spirit level. I find filling raised beds is usually made much more satisfying with some enthusiasm and maybe a glass of real ale! The task is then usually done in no time.

Benefits of raised beds

  • Ease of access
  • Less soil compaction
  • Less erosion of soil and spill
  • Better temperature control in spring, less likely to be in frost-pockets
  • Easier to maintain and weed than traditional bed

Materials used for raised beds

The most common form of raised bed is the wooden raised bed style you can see above. Though a raised bed can be made of any material.Raised beds can be made of metal, brick or stone if required. Usually, wood is the easiest to work with for raised beds and lends itself to a garden. I prefer raised beds made from wood as they blend in with nearly all surroundings this means that you can use them for a variety of different planting plans.

Planting begins

Measuring up for raised beds

You need to accurately measure the space in which your raised bed is going. Even with the largest space, it is always necessary to measure to see exactly how big it will be. Take a pad and always double check your measurements. Accurate measurements are also essential for working out:

  • How much timber you will need
  • Number of screws you may need
  • Amount of topsoil
  • Quantity of plants you can place in your finished raised bed

The measurements you will need are the length, width & height of the raised beds.

Length guide:  

As a rule, any raised beds over 2 meters in length will need braces. I always advise internal braces on all raised beds over 1 meter in length. This is because the soil is really heavy and the pressure on the walls of a raised bed when the soil gets wet can be incredible. Bracing helps strengthen the raised bed.

If you’re going over 2.5 meters in a one-piece raised bed you should really be looking at railway sleepers and steel ties as these are strong enough for really long raised beds.

Another answer is to cut the entire length into a series of smaller raised beds. This also helps as if there is ever any damage you can just replace one of the beds, not the entire raised bed! This can also be helpful as sometimes boundaries and adjacent walls are not entirely true, ie they may run on a slight angle. By using multiple beds, you can make micro adjustments to give the illusion of a straight line.

raised beds garden ninja rustic 5

Reclaimed teak timber raised bed

Width guide:

I usually recommend at least 90cm in width if you want to be able to plant two rows of plants. Thinner widths can be used especially for balcony planting and beds in restricted spaces. For vegetable plots, I would recommend between 50cm and 90cm. Anything over 1 meter will be difficult to reach over unless you plan to have access on all sides.

Height guide:

As a rough rule, 6 inches or 15cm is the minimum depth you will need. Any shallower than this and you will need to work over the ground underneath. Since most people using raised beds are trying to avoid this you will need 15cm of topsoil for new planting. Also, if you are planting on top of a hard surface this is the minimum depth

How to make a raised bed

Making a raised bed is not difficult though it does involve plenty of planning and measuring. It also requires some key tools which you will need.

  • Wood saw (Heavy duty or fine depending on the thickness of the wood)
  • Screwdriver
  • Electric Drill & Bits
  • 75mm Stainless Steel Screws
  • Mitre saw (Optional)

Raised bed guide

1.  Once you have your measurements double check that they fit the space where the raised bed will go.

2.  Cut your boards to the length you require them using your wood saw. For a 1m long raised bed the boards should be 1mt long. You then need to multiply the width of each individual board by the height you need the bed to be. This will give you how many 1mt boards you need per side. So if a board is 30cm wide and you want your bed 60cm high you will need two boards for each length.

2.  Next cut the boards for the sides of the raised bed, also known as the depth. These will be your side panels. ie a 90cm deep raised bed will require a 90cm long board for your side panel. Again, cut enough boards to make the required height. You will need to ensure the braces on the side boards are recessed. If they are dead on the edge they won’t provide a flush joint, as they will butt up against the other brace, when joined to the front and back panel.

You will need to ensure the braces on the side boards are recessed. If they are dead on the edge they won’t provide a flush joint, as they will butt up against the other brace, when joined to the front and back panel.

 

3.  You then need to use braces to secure the rows of board or timber. The photo below shows how the braces can be positioned. It also shows you the front view with the screws going through the face of the raised bed side to the brace. Measure the height of your bed and then cut enough braces for the faces of the bed. A minimum of two on each face should be used.  I usually use three for strength.

4.  Drill a pilot hole and then screw these braces, from the facing side inwards, using your 75mm screws. Decking screws can also be used but be careful as some can rust and stain your wood.

5.  You should now have 4 pieces. 2 Long panels and 2 shorter side panels. The long being the length. The shorter is the depth.

raised beds garden ninja rustic 3

Garden Ninja making raised beds

6.  Once you have your four sides braced, you can start to screw the sides together. Drill pilot holes and then screw the edges together. Use clamp supports or a helping hand to keep them steady whilst you position them.

7.  Once all the screws are in you then need to add another brace to the inside of the raised bed. This ideally should be placed in the middle and stops the raised bed from bowing when full of soil. It also adds strength to your raised bed.

raised beds garden ninja brace 1

8.  Once that’s complete double check your bed for signs of movement or any joints that don’t feel tight and secure. Ensure all screws are tightened before you move or add the lip.

Optional Mitered Raised Bed Lip

9.  You can now add a mitred edge or lip if you so wish. This gives the raised bed a more finished look and somewhere to rest your tools, plant pots or a pint of beer! For this, you will need to measure the length on a new board and mark it up. Then, using a mitre saw set to 45 degrees, cut from that measurement. Do this on each side flipping the mitre to the opposite 45-degree angle so the cuts face away from each other. Measure the sides and do the same ensuring they fit neatly before screwing them into the raised bed.

raised beds garden ninja mitre joint

Once this is done your bed should be complete!

Filling your raised bed

Now you have your raised bed in the position you can start to fill it with a soil of your choice. I have a detailed article on why soil type matters that you can read here. Ideally, you want a mix of loam and good organic matter in your beds. If you have taken up turf underneath the beds then you can use this in the bottom. Simply turn the turfs upside down and line the base of your raised bed with them. Which is a great way to recycle and save costs on buying soil!

Raised beds on turf or soil

You can simply start to fill the raised bed up with topsoil. Now is a useful time to improve the drainage of the ground the raised beds going on, especially if it’s going onto a heavy clay soil or where the drainage is poor. Fork it over and add organic matter before you fit the bed. Preparation is really key, if you put a raised bed onto compacted ground you can end up with ‘wet bed’. My guide to improving compacted soil can show you how to quickly improve soil conditions.

Raised beds on tarmac or flags

If your raised bed is placed on a non-porous surface such as tarmac or flags it may be useful to break into one of the flags to allow for drainage. This will allow drainage and stop water pooling at the bottom or cause ‘wet bed’. The wet bed is where the bottom of the beds are always damp as the drainage causes a backlog of water. If you’re sitting the raised beds on ungrouted flags then the need for drainage is probably unnecessary, it’s only if the surface is non-porous or slow to drain.

raised bed guide

Drainage for raised beds

You need to remember to leave a gap between the very top of the bed and the soil level. I’d always leave a 2-3 inch gap between the very top and the level of the soil. This helps prevent the soil spilling over onto the surrounding area. It also means that any small or new plants are slightly protected from any wind or immediate exposure. When plants are young or new any harsh winds can damage or slow down their ability to take root. It also means that when you water your plants there’s no spillover of wet muddy water!

filling raised beds garden ninja

When filling the raised beds with topsoil, I’d always advise mixing in some compost or organic material to assist your new plants in taking root. You need to ensure that the soil is of a PH that is suitable for your plants, ideally neutral at 7 for most plants. If you’re planting acidic loving plants you may need to acidify the soil such as adding pine needle mulch.

raised bed guide

Filling raised beds

Once filled you can then start to lay out your plants. I advise you always work to a planting plan, if not you may end up with ‘pick and mix planting’ where you just plonk things here and there and the overall look becomes a bit of a jumble.

To make the best of your raised bed you need a cohesive planting plan. Usually, a good tip is to have the taller plants at the back, if it’s a bed against say a wall and then smaller planting towards the front. If it’s a bed you can walk all the way around it can be a good idea to have the height in the middle with a row either side of plants? The possibilities are endless, but must be well thought out!

raised bed guide

Contemporary raised beds in garden design

Summary

Ultimately raised beds come in all sorts of shapes and sizes and a multitude of materials. Raised beds are great for a quick fix garden design and can be incorporated into any garden a recent family garden transformation utilised them excellently and can be seen here. Whether it is growing your own veg or planning your own amazing garden design, raised beds are an excellent choice. Do you have your own raised beds you want to show off? Why not send Garden Ninja pictures at [email protected]

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