Soil for raised beds – which soil, and how much do you need?

A raised bed is one of the easiest ways to grow vegetables, herbs and flowers. The soil warms up quickly in spring, you get a comfortable working height, and you decide which soil the plants grow in. But the soil is exactly what makes or breaks a raised bed.

In this guide you find out which soil is best for raised beds, how to fill a raised bed, how to save on soil, and how much soil you need.

Which soil is best for raised beds?

Plants in a raised bed grow close together and quickly, so the soil must hold both water and nutrients – while draining away excess water. That is why we recommend a soil blended for the purpose:

Raised bed soil from Grobund™ is approved for organic growing and enriched with Danish soil improvers. It contains moler (diatomaceous earth) from Mors, which can absorb water and nutrients and release them to the plants when they need them.
Herb soil is a good choice if the raised bed will mainly be used for herbs that prefer well-drained soil.

Ordinary garden soil from the rest of the garden is rarely ideal in a raised bed. It is often too heavy or too low in nutrients and settles quickly.

How to fill a raised bed

Prepare the bottom: Remove the turf and loosen the soil at the bottom so water can drain away. If you have problems with mice or moles, you can lay fine-mesh wire at the bottom. Avoid plastic, as it blocks drainage.
Bottom layer (in tall beds): If the raised bed is more than approx. 50 cm high, you can fill the lower part with topsoil or coarse branches and brushwood. The branches break down slowly and add nutrients.
Top 30-40 cm: Fill with raised bed soil. This is where the plant roots grow, so this is where the best soil should be.
Fill right up: Fill the soil right to the edge – it typically settles 10-20 % after the first rain and watering.
Water thoroughly, and top up if the soil has settled a lot before sowing and planting.

Cheap soil for raised beds – how to save

A large or tall raised bed needs a lot of soil. To keep the cost down you can:

Use two layers: Topsoil at the bottom and raised bed soil in the top 30-40 cm, where the roots are.
Fill the bottom with branches: In very tall beds the lower part can be filled with branches, brushwood and prunings from the garden.
Buy in larger quantities: If you are filling several raised beds, it is cheaper to have the soil delivered in a bulk bag rather than buying many small sacks.

How much soil does a raised bed need?

Calculate the quantity like this:

Length (m) × width (m) × height (m) = m³

1 m³ equals 1,000 litres. Here are some examples:

Raised bed 2 × 1 m, 40 cm high: 0.8 m³ = 800 litres
Raised bed 2 × 1 m, 60 cm high: 1.2 m³ = 1,200 litres
Raised bed 3 × 1.2 m, 50 cm high: 1.8 m³ = 1,800 litres

Add 10-20 %, as the soil settles. See more examples in How much gravel, sand and soil do I need?, or use our quantity calculator.

How to keep the soil in your raised bed healthy

Add soil conditioner every year: The plants use up the nutrients and the soil settles. Each spring, top up with 3-5 cm of soil conditioner and mix it lightly into the top layer.
Rotate crops: Avoid growing the same crop in the same place year after year.
Cover the soil: A layer of grass clippings or straw between the plants retains moisture and suppresses weeds.
Water regularly: Raised beds dry out faster than in-ground beds, especially in summer.

Read more about growing vegetables in Getting started with a vegetable garden, and about improving soil in How to Improve the Soil in Your Garden.

We deliver raised bed soil and topsoil in bulk bags directly to your address – read more about delivery.