Why determine soil texture? If you’re a gardener, more than likely you understand that plants grow best in conditions that are ideal.
Plants want the right amount of sunlight, the right amount of water and the right amount of nutrients. You may also know that plants want rich soil to grow in.
But have you considered the soil texture?
What is that?
In this article, I’ll break down what soil texture is, why it’s important to understand and how to determine the soil texture that you have.
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Why should I determine the soil texture?
There are three main reasons that soil texture is important.
Soil texture can be a make or break for you, no matter if you’re a small gardener, a large row-crop operation or if you’re just trying to plant flowerbeds or grow a decent lawn.
In other words, all plants are affected by soil texture. But what does the texture of the soil have to do with plant growth?
Roots want to grow in the easiest soil that they can. They don’t want to have to work harder than they have to in order to grow and find nutrients.
Really hard, compact soil can prevent root growth.
Soft soil will increase root growth, therefore increasing plant growth and productivity.
This is especially true for young seedlings and baby plants. You can make sure that you have tougher plants by starting your seeds indoors and then bringing the older seedlings into the garden if your soil is tough.
Soil that has adequate drainage will keep both air and water available to the root system.
This also means that nutrients are more available to the roots also. Soils that hold too much water will drown the plants on them.
Properly drained soils are of less risk to erosion and nutrient runoff.
Plants require nutrients, water and air (typically oxygen) at the root system.
In order to access nutrients and air, there needs to be adequate space in the soil for the air to reside. If the soil is too compacted it will not have pockets that can hold air.
The plant needs to be able to take in oxygen and carbon dioxide at the roots in order to grow properly.
Air in the soil is also important for the beneficial organisms that live around the roots in the soil.
Determine Soil Texture- Components of Soil
There are six main components that make up soil- air, water, organic material, sand, silt and clay. When looking at soil texture, sand, silt and clay are the components being viewed. These three particles are what make up the soil.
You can think of the texture as being how the soil feels. Is it rock solid when dry or does it crumble apart easily? Is it slick when wet or is it gritty? The way the soil feels can give you an idea of the soil texture.
Sand is the largest soil particle (ranging in size from 0.05mm to 2.0mm). A grain of sand is typically light in color and can be easily seen with the naked eye. Sand particles are large and oddly shaped. This creates a larger air space in between the grains.
When rubbing sandy soil in your hand, the sand will cause the soil to feel gritty when dry or wet. Because of this grittiness, sandy soils are often called coarse-textured soils. If you try to squeeze a ball of sandy soil, it won’t hold a shape but will crumble easily.
Sandy soils are usually extremely well-drained and some can be overly drained leading to soils that are susceptible to drought.
Silt particles (ranging from 0.05mm- 0.002mm) are smaller than sand but larger than clay. This particle holds more water than sand, but doesn’t hold as much water as clay. This is because of the moderate size of the particles. The particles pack together closer than sand, leaving less room for drainage to occur.
When you rub silty soil in your hand, it will feel smooth. If you try to make a ball with silty soil, it will hold the shape but can be easily changed.
Clay particles (less than 0.002mm in size) are the smallest soil particles. They hold the most water and are therefore the least drained of the particles. Clay is extremely sticky or gummy when wet. In fact, it only takes about 20% clay in a soil to make it sticky.
A moist ball of clay will resist breaking in your hand. A dry clod of clay soil is very hard to break. Clay will coat your hands if it is wet and usually has a shine to it.
Soil Texture Classes- The Scientific Way to Determine Soil Texture
There are 12 classes of soil texture. These classes describe the amount of each soil particle that exists in the soil in percentages. These classes are best described by using the soil texture triangle below.
The soil texture triangle shows how the different soil texture classes are determined.
Understanding the percentages of different particles in the soil are good to know, but how can you determine the soil class at home without sending them to a lab for testing?
Determine soil texture class easily at home
To figure out the texture class of your soil, you can follow a few steps with soil and a little bit of water in a spray bottle.
Start by taking about 25 grams of soil in your hand. Mist the soil with water and knead it in your hand to break down any clods or clumps. You want the soil to be moldable and pliable, similar to moist putty.
Once the soil is moist, squeeze it into a ball. Does it remain in a ball when you squeeze it?
If not, is it too dry? If it’s too dry, add more water. Soil that isn’t too dry may be too wet. Add more soil if it’s too wet until you have the right consistency. If it’s not too wet and doesn’t stay in a ball, then it’s most likely sand.
If it stays in a ball when squeezed, place a ball of soil between your thumb and forefinger. Gently push the soil with your thumb and squeeze it upwards into a ribbon. Try to form a ribbon that’s uniform in width and thickness. Keep pushing the soil into a ribbon, allowing it to emerge and extend over the forefinger, breaking from its own weight.
Soil that won’t form a ribbon is loamy sand. If it forms a ribbon, measure the length and continue to the next steps.
Soil that forms a weak ribbon less than 2.5cm long-
Excessively wet a small pinch of soil in your palm and rub it with a finger. If it feels very gritty, then it’s sandy loam. Does it feel very smooth? Then it is a silt loam. Soil that doesn’t feel either smooth or gritty is loam.
Soil that forms a medium-sized ribbon that is 2.5-5cm long-
Excessively wet a small pinch of soil in the palm of your hand and rub it with a finger. If it feels gritty, then it is a sandy clay loam. Soil that feels very smooth is a silty clay loam. Doesn’t feel gritty or smooth? Then it’s a clay loam.
Soil that forms a strong ribbon that is over 5cm long-
Excessively wet a small pinch of soil in the palm of your hand and rub with a finger. Soil that feels very gritty is sandy clay. If it feels very smooth it is silty clay. If it doesn’t feel gritty or smooth then it is clay.
Now that you’ve determined your soil texture, you can make amendments if needed to get your soil to an ideal texture. Remember, you want to avoid sandy soils or clayey soils. Somewhere in the middle is best.
Determine Soil Texture and Amend It if Needed
One of the easiest ways to fix soil texture is by adding organic matter. Organic matter will break up the texture, whether it is too clayey or too sandy. It will also improve the drainage, aeration, water and nutrient holding capacities.
Organic matter that you can add to your soil includes compost, mulch, decomposing leaves, grass clippings or manure. Stay away from meat-based organic material and stick with plant-based organic material for the best results (egg shells, bone meal and bone char are exceptions).
I use chicken manure in my garden. Read this post to see how I minimize cleaning out my chicken coop and maximize my garden soil health. I don’t recommend using pig manure as a garden soil amendment. But, it is important to have a pig manure management plan if you raise pigs.
Too much clay
If your soil has too much clay, there are several ways that you can break it up.
You can add coarse sand. This is an easy option for garden beds. The sand can be tilled into the soil to help break up the clay clods. Pea gravel can also be added to break up the hard texture of clayey soils. Perlite or vermiculite are cheap options that can break up the clayey soil. Many garden stores don’t carry them since they are more of a specialty item sold for hydroponic and greenhouse growers.
Too much sand
If your soil is too sandy, you could locate clay and add to your soil to give it some water holding capacity. Perlite can also be added to sandy soil to hold water.
If you find out that you have terrible soil, don’t worry. You’re not alone! I live in an area that has some of the worst clay soil. In fact, a few years ago, we couldn’t figure out why our garden was either always soaked or always bone dry. Come to find out, when we dug down into the soil, not only was the top 12-18″ almost pure clay, but there was a layer of hard sandstone underneath. No wonder! After a year or so of working on the soil, that garden plot was extremely productive.
Soil can be fixed if you know what needs to be done to it. I work on my soil starting in the fall each year. Read this article about fall soil amendments to see how you can work on your soil in the winter.
What kind of soil do you have where you are? Have you added anything to your soil to fix it? Leave me a comment below and let me know!