How to build raised garden beds in four easy steps (2024)

If you need more growing space in your garden, learning how to build raised garden beds is a quick and effective way to create room for flowers, plants, shrubs and vegetables. They provide a versatile and quick access platform that offers easy maintenance.

That’s why raised garden beds are often an integral part of

garden design

. When designing a new outdoor space you can choose where you want them to go and decide what type of foliage and greenery will enhance the space.

Here we give you the knowledge and know how to start building your own today.

How to build raised garden beds: step-by-step

When building a raised bed there’s plenty of choice on materials and sizes. Here we show you how to build a raised bed with wood. But the same principles can be applied to other materials.

Before starting, you'll need a couple of key materials and tools, including:

Wooden planks/boards
1” x 1” timber (optional)
Drill
Screws
Topsoil
Compost

1. Plan ahead

Before you start, work out where you want to place your raised bed. Ideally you want to make sure that the bed will be exposed to sunlight and not hidden in the shade from shrubs, bushes, hedges and fences.

2. Prepare the ground

Once you have decided on where you are going to build your raised bed you need to prepare the ground. Typically, raised garden beds are placed on top of turf.

Measure and mark out where the bed is going with wooden pegs and string. Get a spade or a lawn edger like the Draper Carbon Steel Lawn Edger from Amazon and cut the turf around the marked out area.

Now get a spade and skim off the top layer of turf across the whole marked out area and place out of the way. Once the turf has been removed, get a garden fork and turn over the soil and remove any weeds.

3. Build your raised bed

With your chosen wooden planks, start to assemble your bed. If using scaffold boards, or pine decking planks you will need to use some 1” x 1” timber to hold the boards or planks together.

Cut four lengths the same height as the boards/planks and cut a shallow point on the end of each length. Now screw each length – an inch or two down from the top edge – into the boards/planks on each corner to create the rectangular base of your raised garden bed.

Now measure both diagonals to make sure the frame is straight. If both diagonals are the same length you have done a good job.

4. Add topsoil and compost

Raised beds are for growing plants or vegetables, so you don't want to be using any old soil from your garden. You need to fill your new beds with a mixture of topsoil and compost to make sure that the soil has enough nutrients to grow the plants or vegetables you choose.

You will also need to regularly add more compost or organic material to make sure that the soil stays healthy for growing. On this note, now is a great time to try

organic gardening

methods to make your raised garden beds more environmentally friendly.

Make sure to leave the soil for a week to let it settle. If needed, add more soil/compost mixture in areas that have sunk further than others and leave to settle again.

What size should I make my raised beds?

Raised garden beds are typically around six to eight feet long (1.8-2.4m), around four feet (1.2m) wide and anywhere from six inches (around 15cm) to three feet (90cm) or more high.

The length of a raised bed is subject to choice. An ideal size is around eight feet, but can be shorter or longer depending on space and what you want to grow.

The width of a raised bed is more important. You don’t want to be treading on the bed and compacting the soil. So four feet is probably the maximum, but make it narrower if you are not comfortable leaning across this distance, or can't gain access on both sides.

The height is typically the width of the wood chosen, but you might want to double or even triple up on the height depending on what you are growing.

What wood should I use when building raised beds?

The popular choice is pine as this is relatively inexpensive and easy to get hold of. Oak and cedar are also popular but more expensive than pine. You could look for recycled scaffold planks or decking to keep the price down.

The issue with wood is that it will rot over time and needs replacing. It’s a good idea to treat it with a suitable preservative like

Ronseal Matt Decking Protector from B&Q

before you build the raised bed.

What is the cheapest way to build raised garden beds?

Pine decking is one of the cheapest easy ways to build a raised garden bed. If you do some scouting around on the web you can find some really good deals. Reclaimed scaffold boards are another inexpensive wood that does a good job.

If you want something ready to go you can take a look at the

Verve Large Raised bed kit from B&Q

. It's not as cheap as building your own raised bed, but it does mean you can start planting sooner.

Wood is not the only cheap option for building a raised bed. Concrete blocks and some bricks can be relatively cheap, easy to lay and will last longer than wood.

How high should you fill a raised bed with soil?

The simple answer is that you fill to the top of the raised bed and leave to settle. The height of a raised bed needs to be high enough to contain whatever you are planting or growing. Most plants and vegetables need around one foot (30cm) of soil to grow, but if you are placing your raised bed on soil, six inches (around 15cm) is enough.

If you want easier access to the soil – maybe you don’t want to be bending over too far – building a higher raised bed is the answer.

Do you need a membrane under raised beds?

Typically you wouldn’t need to place a membrane under raised beds if they have been placed on open soil and weeded.

However, if you have a shallow raised bed that has a lot of weeds in the soil, it is a good idea to lay down a membrane.

Cardboard is a good cheap choice as it will suppress weeds and grass and will naturally decompose making it an ideal choice of your looking for low maintenance garden ideas.Alternatively, a designated weed membrane can be used.

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Now, let's discuss the concepts mentioned in the article about building raised garden beds.

Benefits of Raised Garden Beds

Raised garden beds are a popular choice for gardeners looking to maximize their growing space. They offer several advantages, including:

Increased Growing Space: Raised garden beds provide additional space for growing flowers, plants, shrubs, and vegetables in your garden.
Versatility: These beds can be placed anywhere in your outdoor space, allowing you to choose the best location for sunlight exposure and aesthetic appeal.
Easy Maintenance: Raised garden beds are easier to maintain compared to traditional gardens. They provide better control over soil quality, drainage, and weed management.

Steps to Build Raised Garden Beds

Here is a step-by-step guide on how to build raised garden beds using wood:

Plan Ahead: Determine the location for your raised bed, ensuring it receives adequate sunlight and is not obstructed by shrubs, hedges, or fences.
Prepare the Ground: Clear the area of any turf or vegetation. Use wooden pegs and string to mark the boundaries of the bed. Remove the top layer of turf and turn over the soil using a garden fork to remove weeds.
Build the Bed: Assemble the bed using wooden planks. If using scaffold boards or pine decking planks, use 1" x 1" timber to hold them together. Screw the timber lengths into the boards on each corner to create the rectangular base. Ensure the frame is straight by measuring both diagonals.
Add Topsoil and Compost: Fill the raised bed with a mixture of topsoil and compost. This ensures the soil has enough nutrients for plant growth. Allow the soil to settle for a week, adding more mixture if needed.

Size and Material Selection

When building raised garden beds, consider the following factors:

Size: Raised beds are typically 6-8 feet long, 4 feet wide, and 6 inches to 3 feet high. The length can vary based on available space and personal preference. The width should be narrow enough to avoid compacting the soil, but wide enough for comfortable access.
Wood Selection: Pine is a popular and affordable choice for raised beds. Oak and cedar are more expensive but offer greater durability. Recycled scaffold planks or decking can also be used to reduce costs. Treat the wood with a suitable preservative before building to prevent rotting.

Alternative Materials and Cost Considerations

If wood is not your preferred material, there are other options available:

Concrete Blocks and Bricks: These materials are relatively cheap, easy to lay, and more durable than wood.
Cost Considerations: Pine decking and reclaimed scaffold boards are cost-effective options for building raised beds. Additionally, ready-to-go raised bed kits are available for convenience, although they may be slightly more expensive.

Soil Depth and Membrane Usage

Consider the following factors when filling your raised bed with soil:

Soil Depth: Fill the raised bed to the top, leaving enough space for plant growth. Most plants and vegetables require around 1 foot of soil, but 6 inches is sufficient if the bed is placed on existing soil.
Membrane Usage: If the soil beneath the raised bed has a lot of weeds, consider placing a membrane, such as cardboard or a designated weed membrane, to suppress weed growth.

Remember, these guidelines are based on general practices for building raised garden beds. It's always a good idea to adapt them to your specific gardening needs and consult local gardening resources for additional guidance.

Let me know if there's anything else I can assist you with!