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How to Test Soil Texture: One Key to a Lush Garden

A Gardener Is Checking The Soil Texture.

We aren’t happy campers with a tight pair of shoes, and neither are our plants.  The right soil texture gives your plants the best base for healthy growth.  We’re going to discover what soil texture is, and how to test soil texture using several methods.

Once you know your soil texture, what do you do?  These tests could give you good news and you won’t have to do anything!  Otherwise, we offer helpful tips on how to get the correct it.

What is Soil Texture?

Soil texture is the mixture of soil particles made of sand, silt, and clay. They make up the mineral parts of the soil.  Lighter soils have more sand, and heavier soils have more clay.  The proportions of these materials determine:

  • How well the soil can hold moisture.
  • How fast water can move through the soil.
  • How aerated the soil will be.
  • How fertile and workable the soil will be.

Is Soil Texture the Same as Soil Structure?

Texture describes how much sand, silt, and clay is in the soil.  So you could say the texture is all about the individual particles in the soil.

Soil structure, on the other hand, describes the arrangement of the particles.  They can be aggregates, layers, columns, or blocks.

Tilling the soil every year can change the soil structure, but not in a good way. Many gardeners have turned to no-till gardening to keep their soil in peak condition.

Soil layers and structure.
Soil structure describes how the soil is built. Structure forms by the arrangement of soil particles. In this picture, we can see some aggregates in the upper layer and blocks of clay below.
A farmer's hand showing soil texture.
Soil texture describes the proportions of sand, silt, and clay in a soil sample. It determines soil fertility, drainage, and suitability for growing crops.

What Makes Up Healthy Soil?

Healthy soils comprise 40 – 45% mineral solids, 50% pore space (to hold air and water), and 5 – 10% organic material.

Soil can be fertile with organic matter but still not grow plants well.  Without the proper proportions of sand, silt, and clay, all that fertility is nearly useless.

Soil Texture Tests You Can do at Home

Tests for texture give us a picture of the type of soil based on the mineral solids.  You can do some simple tests at home to determine it, like The Squeeze Tests and The Jar Test.

The Squeeze Tests

Video: Soil Texture by Feel

Refer to the above video for examples. These tests will give you a general idea of the texture.  For more detailed results, see The Jar Test below.

  • Remove the first two inches of soil so you won’t have loose organic material.
  • Loosen some of the exposed soil and wet it enough to form it into a mass the size of a ping-pong ball.
  • Gently squeeze it between the ball of your thumb and the edge of your index finger.

If the soil has excess amounts of sand, silt, or clay, you’ll feel one of these three things:

  • Soil that feels gritty has lots of sand.  This soil drains quickly, so it doesn’t hold moisture.  Another issue is that it’s also poor in nutrients.  Sand makes up the largest particles in the soil.
  • If it feels like moist talcum powder, the soil is silty.  This fertile soil drains well and holds moisture better than sand.  Silt particles are smaller than sand.
  • Slippery soil has lots of clay.  This soil is rich in nutrients but drains slowly.  Clay particles are the smallest.

Do these tests next:

  • Reform the ball in your hand, squeeze it, and release it.  If the soil crumbles, it has a balanced texture (a good mix of sand, silt, and clay).  Soil with a balanced texture is loamy soil, and it’s preferred for gardening.
  • If the soil ball holds its shape, it has a lot of clay.  It has even more clay if you can roll it into a sausage or press it into a ribbon.
  • Take your other hand and slide it over the soil.  Much sand is present if you can see scratch marks on the surface.  If it feels greasy, there’s a lot of silt.

Loamy soil is often ideal for gardening since it forms many pore spaces.  These spaces hold air and water, so the soil doesn’t crust over like clay soil.

The Jar Test

This test allows you to measure the soil’s sand, silt, and clay percentages. Since you’re making measurements it’s more accurate than the Squeeze Tests.

Well-balanced, loamy soil will have about 40% sand, 40% silt, and 20% clay.  Here are the steps for The Jar Test:

  • Find a clear jar with straight sides.  Peanut butter, mayonnaise, or mason jars make good candidates.
  • Go to the soil you want to test and remove the upper two inches.  This will lessen any loose organic material getting into the test.
  • Dig into the exposed soil about six inches and remove enough to fill the jar about halfway.  Taking a sample six inches deep means getting the soil where the roots are growing.
  • Break up any large pieces of soil.
  • Sift the whole sample to remove any stones or large organic particles.  If the soil is damp, put it on a tray for a day or two to let it dry.  That way, it’ll be easier to sift.
  • Put the sifted soil in the jar, add a teaspoon of dish detergent, and fill the jar to about 1/2 inch from the top.  The detergent will help to separate the particles.
  • Close the jar and give it a vigorous shaking for three minutes.
  • Set the jar on a flat surface for at least 24 hours.

A Friendly Piece of Advice:

Don’t forget to check for stones in the soil. I was about 10 years old the first time I did this test, and I liked to take shortcuts. I shook the jar, but I didn’t bother taking out any stones first. My hairless young face froze when I saw what those stones can do to the bottom of a glass jar…

After 24 hours, three distinct layers should settle in the jar.

If there’s heavy clay in the soil, the water could still be cloudy.  In that case, settling the remaining clay could take 48 more hours.  There could also be loose organic material floating in the water.

The layers settle based on the particle sizes, with sand being the largest and heaviest. Once the water is clear enough to see through, do the following:

  • Measure the total height of all the layers.
  • Measure the thickness of the bottom sand layer.
  • Measure the thickness of the middle silt layer.
  • Measure the thickness of the top clay layer.

Let’s suppose that we measure all the layers, and they total three inches high.  Then we measured the height of each layer and the sand was 1-¼ inches, the silt was 1 inch, and the clay was ¾ inch.  Then our percentages of sand, silt, and clay would be:

1.25/3 = .417 = 42%1/3 = .33 = 33%.75/3 = .25 = 25%

A handy chart called the Soil Texture Triangle shows how to interpret these numbers.  The percentages on the chart show that this soil sample would be “loamy.”  That means it’s the ideal texture for growing almost all garden crops.

This article won’t discuss how to use the Soil Texture Triangle.  Instead, you can download the instructions at the link below. We also have a video on how to use the triangle.

Download The Soil Texture Triangle Here

Video: The Soil Texture Triangle

Correcting Soil Texture Problems

Adding compost is an excellent way to improve soil fertility.  It also helps sandy soils hold water and clay or silt soils drain better.

  • If the soil is too sandy.  Add compost to improve water retention and fertility.  Add clay soil to balance the soil.
  • If the soil is too silty.  Add compost to improve drainage and fertility.  Add coarse sand to balance the soil.
  • If the soil has too much clay.  Add compost to improve drainage and fertility.  Add coarse sand to balance the soil.

Here are other tests to give you an idea of the soil structure:

The Perc Test

This is another way to see if the soil has too much clay.  You don’t want to do this test after it rains since the soil should be somewhat dry to slightly moist.  Dig a hole about 1 foot deep and 1 foot across.  Fill the hole with water and wait for it to drain.

When the water drains completely, immediately fill it with water again.  This time, you’ll have to see how long it takes for the water to drain.  If it takes longer than eight hours, the soil doesn’t drain well.

The Water Test

This test for your garden soil will tell you if drainage is too fast, which means the soil is too sandy.

  • Thoroughly water the soil surface in a small area of your lawn or garden.
  • Two days later, dig a small 6-inch deep hole where you did the watering.
  • If the soil is dry all the way down the hole, then your soil doesn’t hold water long enough to allow good plant growth.

You can also measure soil moisture with a sensor.  Use the sensor a few days after a good watering or soaking rain.  If the meter shows your soil is too dry, then your soil needs help holding water.

Correcting Drainage Problems Found by the Tests

1. Soil With Slow Drainage

The best way to correct this problem is by adding organic matter to the soil; compost is a great solution.  Adding organic material to soil solves many problems.

Mixing sand with the soil will also improve drainage, but it doesn’t add fertility.

2. Soil That Drains Too Fast

Like slow-draining soil, compost can also solve this problem.  Adding clay to the soil also helps, but it won’t add more fertility.

Ready to continue discovering the wonders of soil testing?  Check out our articles on testing soil for pH and nutrients and how to revive dead soil.

Bob Styer

As a child, I hated gardening. That was mainly because Dad expected us to work in the garden every so often even though we thought play was more important. Over the years, though, I've developed a real appreciation for growing things. Whether you're growing plants for food or to enjoy their beauty, gardening can make your life better. Seize the moment!

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