How to determine soil texture

Soil texture is defined by the proportion of sand, silt and clay-sized mineral particles in the soil. Different soil textures have different characteristics which can influence the success or limitations of different management practices. Soil texture can be determined by hand or by sending a sample to a laboratory.

Soils are commonly grouped by texture – the proportion of primary particles (sand, silt and clay).

Texture determines how easy the soil is to work and can indicate how resilient the soil is to structural damage.

Marked changes in texture can occur vertically within the soil profile.

Soil texture is also a major factor that controls:

• How much water a soil can hold
• How available water is to plants
• How good it is at holding on to lime or other nutrients (buffer capacity)
• How well roots can grow

It is not easy to change soil texture, but management needs to adapt to it.

Soil texture is classified differently between mineral soils and soils with higher organic matter content; organic mineral and peaty soils.

Mineral soils typically contain less than 6% organic matter and texture class is based on the proportion of sand silt and clay (figure 1).

Organic mineral and peaty soils typically have an organic matter content greater than 20% and texture class is based on the proportion of sand and organic matter content (figure 2).

Figure 1. Soil texture classification for mineral soils with soil management groupings

Figure 1 shows mineral soil textures can be grouped for the purposes of soil management into light, medium and heavy soils. These groupings are: 

• Sandy and light soils that have up to 18% clay and over 82% silt and include sand, loamy sand, sandy loam, sandy silt loam and silt loam textures
• Medium soils that have between 18 and 35% clay and 65 and 82% silt and include sandy clay loam, clay loam and silty clay loam textures
• Heavy soils that have over 30% clay and over 65% silt and include clay, sandy clay and silty clay textures

Figure 2. Soil texture classification for soils with high organic matter

Note: ¹ Less than 50% sand in the mineral fraction. ² 50% sand or more in the mineral fraction

Organic mineral soil typically has between 6 and 25% organic matter. It is typically dark-coloured and smooth with the mineral component dominant. 

Peaty loam or peaty sand has between 20 and 35% organic matter. Peaty loam has less than 50% sand in the mineral fraction whilst peaty sand has 50% or more sand in the mineral fraction. Both peaty loam and peaty sand soil is typically grey, comes together to form a ball and has a smooth feel.

Loamy peat or sandy peat has between 35 and 50% organic matter. Loamy peat has less than 50% sand in the mineral fraction whilst sandy peat has 50% or more sand in the mineral fraction. Both loamy peat and sandy peat soil is typically grey/black, granular and comes together to form a ball which breaks easily.

Peat has over 50% organic matter and is typically black, granular and low density.

Soil texture is determined most accurately by laboratory analysis. However, it is possible to get an indication of soil texture class by hand. Follow these steps to determine a mineral soil’s texture:

1. Take about a dessert spoonful of soil.
2. If dry, wet up gradually, kneading thoroughly between finger and thumb until soil crumbs are broken down.
3. Enough moisture is needed to hold the soil together and to show its maximum stickiness.
4. Follow the paths in figure 3 or the text-version below to determine the texture.

Figure 3. Flowchart showing how to assess mineral soil texture by hand

Answer these questions to assess soil texture by hand:

1. Is the moist soil predominantly rough and gritty?

If yes, continue to question 2. If no, continue to question 5.

2. Does the soil stain the fingers?

If no, this indicates sand. If yes, continue to question 3.

3. Is it difficult to roll the soil into a ball?

If yes, this indicates loamy sand. If no, continue to question 4.

4. Does the soil feel smooth and silty as well as gritty?

If yes, this indicates sandy silt loam. If no, this indicates sandy loam.

5. Does the soil mould to form an easily deformed ball and feel smooth and silky (buttery)?

If yes, this indicates silt loam. If no, continue to question 6.

6. Does the soil mould to form a strong ball which smears but does not take a polish?

If yes, continue to question 7. If no, continue to question 9.

7. Is it also rough and gritty?

If yes, this indicates sandy clay loam. If no, continue to question 8.

8. Is it also smooth and buttery?

If yes, this indicates silty clay loam. If no, this indicates clay loam.

9. Does the soil mould like plasticine, polish and feel very sticky when wet?

If yes, continue to question 10.

10. Is it also rough and gritty?

If yes, this indicates sandy clay. If no, continue to question 11.

11. Is it also smooth and buttery?

If yes, this indicates silty clay. If no, this indicates clay.

Soil texture is determined most accurately by laboratory analysis.

For an indication of the soil texture in a field, you can view online maps that provide 1:50K or 1:250K resolution.

These include:

• UK Soils Observatory (UKSO) Map Viewer or the UKSO mySoil app available in the App Store or Google Play
• National soil data portal for England and Wales provided by Cranfield University, where a free user account must be setup before accessing the data