What is the best material for raised beds?

Timber sleepers are the most popular choice: durable, attractive, and easy to work with. Scaffold boards are a budget option. Brick and stone are permanent but more expensive. Avoid pressure-treated timber if growing edibles — use untreated larch, oak, or cedar.

How high should a raised bed be?

For vegetables, 200-300mm (8-12 inches) is sufficient for most crops. For root vegetables like carrots, 400mm+ is better. For wheelchair-accessible beds, 600-700mm is recommended. Higher beds need more soil but offer better drainage and less bending.

Do I need landscape fabric?

Landscape fabric on the base prevents weeds growing up into the bed and stops soil mixing with the ground below. On the sides, it helps prevent soil washing out between boards. It is recommended for timber beds but not essential for brick or stone.

How much soil do I need to fill a raised bed?

Use the calculator above to get the exact volume. As a guide, a standard 2.4m x 1.2m bed at 300mm high needs about 0.86 cubic metres. A bulk bag holds approximately 0.85m3. Mix topsoil with compost (roughly 2:1) for best results.

GardenCalcs

Raised Bed Material Calculator — Build Your Own Raised Beds

Calculate all the materials needed to build raised garden beds.

Bed Length

Dimensions of the garden bed

Bed Width

Dimensions of the garden bed

Bed Height

Height in millimetres

MaterialMaterial

Number of Beds

Number of beds

How We Calculate This

This calculator works out material quantities from bed dimensions, construction material, and number of beds.

Calculations

Courses high = Bed height / material height (rounded up)
Material count = Units per course around perimeter x courses x (1 + overlap%)
Landscape fabric = (Base area + side area) x (1 + overlap%)
Soil volume = Length x Width x Height
Bulk bags = Soil volume / 0.85 m3 per bag

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.