How to Make a Raised Bed

Building raised beds is a fantastic way to expand your garden, especially when your soil isn’t ideal for growing. With a little preparation, constructing a raised bed can be completed over a weekend, giving you an ideal space to grow vegetables, fruit, cut flowers, or even small trees and shrubs.

If you’re new to this, you might also enjoy this step-by-step guide:
DIY Raised Garden Beds

Quick Facts:

• Raised beds can be built year-round, though many gardeners find winter the best time.
• Construct them on free-draining ground for the best results. If you’re building on a hard surface, ensure plenty of drainage holes.
• The size and depth of the raised bed depend on what you plan to grow.
• Pressure-treated timber is a durable material for frames, though bricks, stone, scaffold boards, and recycled plastic are also options.
• Fill beds with a mixture of topsoil, organic matter, and sharp sand for optimal growing conditions.

Why Grow in Raised Beds?

Raised beds offer numerous benefits:

• Improved Growing Conditions: You can fill raised beds with fertile, free-draining soil, perfect for areas with poor or waterlogged soil.
• Faster Spring Warm-Up: The soil in raised beds warms faster, which is ideal for getting an early start on vegetables.
• Better Soil Customization: Raised beds allow you to tailor the soil mix for different types of plants, ensuring optimal growth conditions.
• Accessibility: Raised beds are easier to manage, especially for gardeners with restricted mobility.
• Aesthetics: Raised beds look neat and attractive in any garden, and the elevated height allows you to enjoy plants at eye level.

If you’re just starting out with gardening, check out this helpful guide:
Gardening for Beginners: How to Plant

Getting Started with Raised Beds

Before constructing your raised bed, consider the following:

1. Aspect and Orientation: Most plants need full sun, so place beds in a south- or west-facing area, away from trees or shaded spots.
2. Size: Multiple smaller beds are easier to manage than one large bed. Keep widths under 1.5m (5ft) for easy access to the center.
3. Depth: For most plants, a depth of 45cm (18in) is ideal. Dwarf plants and shallow-rooted crops may require a depth of 30cm (1ft).
4. Pathways: Ensure pathways between beds are at least 45cm (18in) wide for wheelbarrow access or 1m (3½ft) for wheelchair accessibility.

Timber is a popular material, especially pressure-treated softwood sleepers, which last for years. However, untreated wood like recycled pallets or scaffold boards has a shorter lifespan but can be treated with preservatives for extended use.

Tools & Materials You’ll Need

Here are the essential items for building your raised bed, with links to recommended products on Amazon:

1. Durable Timber (Softwood Sleepers) – Pressure-treated wood lasts longer outdoors
2. Heavy-Duty Spade/Shovel – For digging and soil preparation
3. Canes and String – For marking out your bed shape
4. Spirit Level – To ensure your bed is perfectly level
5. Power Drill & Coach Screws – For securing timber frames
6. Wooden Batons – For reinforcing multi-layer beds
7. Rubble/Subsoil – For drainage in deep beds
8. Topsoil – Base growing medium
9. Organic Compost – For soil enrichment
10. Sharp Sand – Improves drainage

Step-by-Step Guide to Making a Timber-Framed Raised Bed

1. Dig a Shallow Trench:

• Mark the bed’s dimensions with canes and string, then dig a trench wide enough to accommodate the timber.

1. Position the First Layer of Timbers:

• Lay the timbers in the trench and use a spirit level to ensure they are aligned both horizontally and diagonally.

1. Screw the Timbers Together:

• Drill through the ends of the timbers and screw them together securely at each corner.

1. Add Additional Layers (If Necessary):

• If you want a higher bed, overlap the joints of the second layer and screw them in place. Use batons to secure vertical corners if using multiple layers.

1. Prepare the Base:

• Remove turf for shallow beds and fork over the soil. For deeper beds, add rubble or subsoil for drainage and top with turves to enrich the soil.

1. Fill the Bed:

• Use a mixture of 3 parts organic matter (compost, leafmould, or manure), 2 parts sharp sand, and 7 parts topsoil. Adjust the proportions for plants requiring good drainage.

1. Let the Bed Settle:

• Fill the bed 5cm (2in) below the rim, firm the soil, and allow it to settle. Topping it off after a couple of weeks will ensure the soil is level and ready for planting.

Frequently Asked Questions

Can I Build a Raised Bed on a Hard Surface?

Yes, but ensure the bed has adequate drainage. Drill drainage holes in timber beds or leave gaps between stones and bricks. Fill the bed with a mix of organic matter, sharp sand, and topsoil, and be prepared to refresh the soil regularly.

Will I Need to Water More?

Yes, raised beds tend to dry out quicker than garden soil. Check moisture levels regularly, and water more frequently, especially during dry or windy conditions. Adding mulch can help retain moisture.

What Other Materials Can Be Used?

• Stone: Strong but requires skilled labor and is often the most expensive.
• Brick: Durable, can create curved beds, but requires footings.
• Paving Slabs: Inexpensive but may need extra support like concrete haunching.
• Recycled Plastic: Extremely durable and low-maintenance, though more expensive.

Raised beds are a versatile and practical solution for improving your gardening space. Whether you’re growing vegetables, flowers, or small trees, creating a raised bed can be a rewarding and straightforward project. Happy gardening!