
Determine the texture of your soil: clayey, sandy, silty
Single tests to assess your soil
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The right plant in the right place, in soil suited to it, is the main requirement for a successful garden. That’s why, whether in gardening books or in our plant fact sheets, you will always find an indication of the ideal soil texture for each plant. But not everyone took “pedology” as a second subject!
The notion of soil texture and terms such as “clay-loam” or “sandy” can seem a little vague.
What are the different types of soils and their characteristics? How can you simply determine your soil’s texture? Here are a few points to help you get to know your soil better.
* the science that studies the formation or evolution of soil
Different types of soil and their characteristics
In terms of pure soil texture, there are mainly three essential components: sand, silt and clay. This is called the mineral fraction of the soil. It results from the breakdown of the parent rock located beneath the soil. These components differ according to particle size:
- sand particles are larger than 0.05 mm (50 µm),
- silt particles range between 2 µm and 50 µm,
- clay particles are smaller than 2 µm.
Note that soils are very rarely purely clayey, sandy or silty: they are often a skilful blend of these three constituents.
Sandy soil
Sandy soil contains at least 60% sand, sometimes more. It has almost no structure: even a small handful of earth crumbles too easily. It is a very easy soil to work and warms up quickly in spring, which favours early crops. However, sandy soil is quite low in fertility because it retains neither water nor nutrients.
Silty soil
Silty soil is rich in silt. It forms from alluvial deposits laid down thousands of years ago — that is, debris carried by flowing water. All silty soils contain at least 10% clay. It is a brown earth, fairly soft to the touch, light and easy to work. It is rich, fertile, very permeable to water and air and warms quickly in spring. It is rather fragile and becomes depleted over the years. It therefore needs regular “feeding“.
Clayey soil
Clayey soil is sticky when wet and cracks when dry. This soil is difficult to work and warms slowly in spring. This type of soil is very fertile and retains water and the minerals needed by plants. But this soil is often very compact, which hampers both rooting and exchange of gases and nutrients.

Various soils: sandy, silty-loamy and clayey
Special case: humus-bearing soil
This is probably the best soil and the one commonly found underfoot in forests. In reality, this refers only to the top layer of the soil. You can therefore perfectly well have humus-bearing soil over a clayey subsoil, for example. Naturally rich in humus, it is very fertile, especially in terms of nitrogen and nutrients. It retains water well, without excess, yet is never sticky. It is very easy to work and is slightly acidic.
What about soil acidity?
There is also much discussion about acidic soils and, conversely, alkaline soils. This also contributes to determining nature of your soil. To learn more, see our advice sheet “Acid soil, neutral soil or calcareous soil: how to tell?“
Read also
What is soil pH?Know your soil texture: single tests
Here are some very basic tests that will quickly give you an idea of the composition of your soil.
The roll or ball test
Take a clod of soil and try to form a roll between your fingers.
- If that is impossible, soil is rather sandy.
- If you form a nice, firm roll, soil is rather clayey.
- If result lies between the two, soil is rather silty.
The soil ball test is quite similar:
Make a ball of soil and throw it roughly onto a flat surface.
- If ball remains intact, soil is strongly clayey.
- If it collapses completely, soil is strongly sandy.
The sedimentation test
Called among agronomists “the jam jar test“, this very simple test is nevertheless highly effective for determining sand, silt and clay content.
To perform this test:
- Take a glass jar of at least one litre, taller than wide and able to be closed with a lid.
- Fill half of jar with soil from your garden, taken at a depth of 10 cm.
- Top up with water leaving a few centimetres of air.
- Close jar and shake vigorously for 3 minutes.
- Let stand for 30 minutes.
- Shake again for 3 minutes.
- L et stand for at least 24 hours: sand, being heavier, will settle at bottom of jar, silt will appear in the middle and clay on top. Particles that float are organic matter; they form a brownish, unappetising layer. If water is still cloudy after 24 hours, wait longer. Decantation can take several days.

Result of a sedimentation test
Handle jar with care so as not to mix strata again. Difficulty will be in distinguishing the different strata. Do your best! Sands are visible to naked eye. As soon as you can no longer distinguish them, you are in the silt. Clay is compact and may have a slightly different colour. Once you have roughly measured the height of each stratum, convert these measurements into percentages using the following formula:
(height of a stratum x 100)/total height = %
In our example, we therefore obtain: 15% sand, 39% silt and 46% clay.
- Finally, to determine the texture of your soil, you will need to transcribe your results onto the soil texture triangle. This triangle allows you to identify the exact name of the soil you tested. To do this, draw a line parallel to the axis for each stratum (see diagram). With the three lines drawn, you will find the intersection point which falls within a zone.

Soil texture triangle (you can find a blank version of this triangle on Wikipedia; others are also available on the Internet)
Here we have a clayey-sandy soil.
Laboratory testing
Sometimes, especially if you have recently moved into a garden or plan to start a specific crop (a large-scale vegetable plot, for example), it can be wise to have a soil analysis carried out by an accredited pedology laboratory. Report provided will indicate, in addition to soil composition: its fertility, level of any pollutants (biocides, heavy metals, …), pH, … as well as possible advice to remedy various issues.
please note : soils, even in small gardens, are rarely homogeneous. You will probably need to take several samples from various locations and average them.
Observing spontaneous flora
Wild organic-indicator plants
Observing native plants in your garden, those formerly called “weeds”, can provide indications about the composition of your soil.
- Predominantly sandy soil: meadow-grass, sea buckthorn, aster, wild lettuce, toadflax…
- Predominantly silty soil: couch grass, fat-hen… but there are few or no plants specific to this soil type.
- Predominantly clayey soil: dandelion, bindweed, vetch, daisy, dock, creeping buttercup…
- Humus-bearing soil: fern, dead-nettle, nettle, sedge, goutweed…

Some organic-indicator plants: meadow-grass, dandelion and nettle
Warning: organic-indicator plants provide only a general indication. Indeed, native plants, especially those we simply call “weeds”, often have a broad ecological tolerance that allows them, even if it is not their preferred habitat, to colonise other soil types. Moreover, as mentioned above, soil rarely consists of a single component. In addition to soil texture, consider structure, moisture, nutrient levels, possible acidity, … In short, nothing beats a proper laboratory analysis.
Seek advice from your neighbours
This may seem obvious, but if your neighbours have been there longer than you, chances are they know their land very well—especially if they are farmers. Their land is their livelihood and they often know results of soil analyses inside out.
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