Soil Types – Identify Clay, Loam and other Soils in Your Garden

It’s useful to know what kind of soil you have in your own garden from time to time. But, first and foremost, what kinds of soils are there? You can identify the soil’s composition by doing a finger test.

What do you mean by “good soil” in your garden? Many gardeners, particularly new ones, have no idea or only have a vague idea of the answer to this issue. You’ve heard talks about the soil in the area, so you’re familiar with it. But what if one’s own land had once been contaminated by various other soils? And how much of what your neighbors say is accurate?

You can find out what kind of soil you have by using our easy guide to checking the soil type. You’ll be able to tell how well particular plants or even your grass do in your soil based on the results of this test.

Different Types of Soils

Soils have been formed over thousands of years from a variety of different raw elements, such as rocks and minerals. There are traces of weathering and organic elements, as well as water movement and rock dust intake.

Because each soil has its own history of development, no two are exactly alike. However, classifying soils – specifically into soil types – is necessary for their comparability.

The varying grain sizes in a soil determine the type of soil that exists. As a result, they show how much of the soil is made up of extremely small, medium-sized, or very large particles. It is possible for soil particles to be as small as 1 micrometer in size or as large as 20 centimeters in size.

Particles of similar size are divided into fractions and referred to as sand, silt, and clay, respectively. The grain sizes of sand, silt, and clay are from coarse to fine. The soil type is determined by the ratio of these three soil constituents. A soil type triangle is an effective tool for remembering this.

#Tip: Loam is not a separate soil grain size category. Soils that have a comparable distribution of all three-grain sizes are referred to as loams. As a result, loams are made up of nearly the same amounts of sand, silt, and clay. These soils are renowned for their fertility. Conversely, soils with a high concentration of a single grain size are often thought to be unsuitable for plant growth.

Sandy Soils

The soil type triangle has sand in the lower-left corner. Due to their main coarse grain size, sand-rich soils are very permeable to water and so have a limited ability to hold water. Waterlogging, on the other hand, is extremely rare in these types of soils.

Sandy soils provide excellent aeration because of the fine sand grains, which allow oxygen to permeate easily. In sandy soils, plant roots take hold quickly, and air-breathing microbes thrive.

Organic matter decomposes quickly in the soil thanks to the active microbes, but regrettably, relatively little humus is produced. This is due to the limited amount of organic matter in sandy soils, which makes them less effective at storing nutrients.

Sandy soils, on the other hand, are a breeze to work because the sand does not adhere to itself or to gardening implements. When it rains, it doesn’t get very heavy due to the fact that it only absorbs a small amount of water. As a result, whenever the term “light soils” is used, it always refers to sandy soils.

With their low pH and susceptibility to lime and acids, sandy soils are particularly vulnerable. For example, there are fine-grained and coarse-grained sands. The terminal moraine of the glaciers during the previous ice age generated sandy soils.

Sandy soils, on the other hand, require regular fertilization and watering, but only in tiny amounts due to their low storage capacity.

Silty Soils

The soil type triangle has silt at its apex. The average particle size of silt puts it in the middle of the clay and sand characteristics spectrum. The pore size of silt is ideal for plant growth because it absorbs water like a sponge and allows the soil to hold more nutrients.

Plant roots, for example, can create negative pressure in order to collect water and then release it quickly because the pores are not too narrow. That’s why sand and silt soils frequently provide for excellent plant sites and result in the most productive of gardens.

A lot of humus can be built up in silt soils, just like in clay. Due to their loose texture and ease of operation, silt soils are great for storing nutrients and water. Sand and loamy silt are types of silt, as are clay and silt. In the foothills of mountain ranges, for example, fertile clay silt is found.

Due to its low stickiness, silt is susceptible to being blown away during dry seasons. Because of this, silt soil should never be left fallow.

Clay Soil

The soil type triangle shows that clays are located in the lower right corner. This soil contains the finest granules, which are clay particles. Clay is defined as anything with a diameter less than 0.002 mm.

Clay, with its small grain size and few interparticle pores, has a high water-binding capacity. However, because the water is so securely contained, most plants are unable to make use of it at all.

Clay minerals have the ability to contract and expand in size. After absorbing water, clay soils are nearly devoid of air. Due to the lack of aeration in clayey soils, many plants and even microbes cannot thrive.

As well as water, clay minerals are excellent nutrition storehouses, therefore they are frequently found to be nutrient-rich. It’s tough to deal with clay because it absorbs so much water, then dries and hardens owing to shrinkage. Whenever you hear the phrase “heavy soil,” you’re talking about soil that’s high in clay.

The production of humus is inhibited in clayey soils because pure clay soil is uninhabitable by microbes and other soil life. It is true, however, that soil with a high percentage of clay minerals has the ability to stabilize humus because clay minerals combine with humus molecules to form “clay-humus complexes,” which are exceedingly difficult to break down and increase soil fertility.

The pH of clay soils is extremely stable, therefore lime or acids only have a very small impact. Silt clays and clay clays are examples of clay soils. Silt clays, for example, can be found all the way from the North Sea up to Hamburg on both sides of the Elbe River, therefore it’s no surprise that fruit cultivation thrives in such areas, as many fruit trees prefer clayey soils.

Even though clay can retain a lot of water, plants are unable to utilize this water in their growth. Heavy clay soil usually has to be mixed with sand in order to support the growth of various plant species. It’s critical to use high-quality potting soil and compost while growing plants in clay soil to ensure humus buildup.

Loamy Soils

Loams are placed at the center of the soil type triangle.  They’re good silt, sand, and loamy soil blend. A large proportion of the water they store may also be used well by plants, therefore their features are seen as particularly desirable by many plants.

They store a medium amount of water, which can be used well by plants. It is possible to build a significant amount of fertile humus with the correct humus management. There are numerous nutrients that may be stored in loamy soils due to their high level of loamy soil and humus.

Loamy soils are therefore rich in nutrients and a sand component of at least 30 percent ensures good soil aeration. But, it is challenging to work with loams due to their high water holding capacity and strong cementing ability.

Sandy loams, normal loams, and clay loams are all different types of loam soils.

Finger Test – Identify the Soil Type in Your Garden

In order to successfully grow an amazing backyard, you must first recognize the soils in your garden. This will help you in choosing the perfect plants and flowers. Don’t worry, recognizing the soils in your garden is very simple.

Finger testing is an easy and surprisingly accurate method of determining soil type. The more soils you have in your hands, the more accurate your estimation becomes. To analyze the finger sample, you must first understand the qualities of the three-grain sizes:

  • Sand has a grainy, abrasive, and scratchy texture. It will not stick to the finger grooves.
  • Silt has a velvety-floury texture to it and isn’t really cohesive. When a surface is smeared, it does not shine. Silt sticks to the finger grooves.
  • Clay has a sticky and cohesive feel to it. That is why it is so simple to shape. When clay is smeared, it creates a gleaming shiny surface.

How to Perform Finger Test

Take a soil sample: In order to do this, collect samples from all across the area being studied. The sample can be taken at a depth of 5 to 20 cm of soil. The top 5 centimeters of each sample should be discarded since it may be contaminated with organic substances and plant debris. In a bucket, thoroughly combine all samples.

Adjust the moisture content: The mixed sample should have a medium moisture content, that is, it should not be wet or dry. This is referred to as “crop moisture” since the water content appears to be ideal for plants. Too-wet soil should be spread out and allowed to dry slightly; too-dry soil should be lightly moistened with a spray bottle.

#1. Rolling Test – A small portion of the test specimen is first forcefully kneaded together in the hand for this purpose. The dough is then flattened out in the palm of the hand to produce a pencil-like roll.

Sample cannot be rolledSandy
Can be rolled once but crumbles on repeated rollingSilty
Can be repeatedly rolledClayey
Roll test results

#2. Rubbing Test – Some of the sample soil is rubbed between the two fingers.

Results ObservedSoil Type Interpreted
feels rough and scratchySandy
feels flourySilty
feels sticky and greasyLoam
All the above can be feltMixed Clay Soil
Rub Test results

#3. Visual and Adhesive Test – The sample is observed carefully and tested for cohesiveness.

Visible grainsMore Sand Proportion
Fine grains sticking to fingersMore Silt Proportion
Dark colorMore Humus
visual test results

Finger sample is prone to error in certain cases:

  • Too-dry samples can be mistaken to be grainier/sandier soil type.
  • Overly damp samples are thought to be more cohesive/clayey soils.
  • Because humus “conveys” both light and heavy soils, clay and sand contents are overestimated, while silt levels are overestimated in heavily humic soils.

Specialized laboratories provide a useful, although not free, option for people who are not confident in their own evaluation of soil type or who require additional details about their own garden soil. In addition to determining the soil type, a soil analysis determines the pH value and the concentration of specific nutrients.

Humus may interfere with soil analysis, yet it functions as a nutrient and water repository in soils and loosens the structure, allowing plant roots to grow more effectively. It is a vital element of fertile soils and food for soil organisms.

Every soil type benefits from increased humus content, which is reason enough to utilize our guide to correct humus management to boost the humus content of your own garden soil!