Soil type is determined by the dominating characteristic of the soil. These characteristics can be grouped into three main categories: clay, sand, and silt soil. However, most soils are a mix of these three soil components and are called loamy soils. Knowing what type of soil you have is an important step in caring for your garden.
To test your soil at home, follow these simple steps:
- Put a handful of lightly damp (not wet) soil in your hand and squeeze it into a ball.
- If it doesn’t hold its shape as a ball at all, you have sand.
- Gently push the soil into a ribbon by pushing the soil between your thumb and forefinger. How it responds determines what type of soil it is.
- If it doesn’t form a ribbon, or a very short ribbon, roll the soil in your fingers. If it feels gritty you may have a sandy loam. If it feels smooth it may be a silt loam. If it is neither gritty, nor very smooth you have a loam soil.
- If you can make a ribbon 2.5 to 5 cm long roll the soil between your fingertips. If it feels gritty you may have a sandy clay loam, if it feels smooth it is a silty clay loam. And if it feels neither gritty or smooth it is a clay loam.
- If you can form a ribbon 5 cm or longer, roll the soil between your fingertips. If it feels gritty you may have sandy clay. If it feels smooth you may have a silty clay. And if it feels neither gritty or smooth you have a clay soil.
Different Types of Soil
As evidenced by the name, sandy soil has a high sand content. It is quick draining but is low in nutrients and moisture. Nutrients wash away in the rain because the soil structure is unable to hold onto the nutrients with more force than the pull of water (polar molecule). Sandy soil is typically acidic, warm, dry, and light. Sandy soil is easier to work with but dries out easily.
Adding organic matter to sandy soil helps with the moisture and nutrient retention in the soil improving the overall structure.
Unlike sandy soil, clay soil is high in moisture and nutrients but does not drain well. With a lack of organic material in the soil, clay soil is often sticky.
Because clay particles are flat, rather than round like sand, clay acts like a stack of paper that is overlapped page by page. You are lucky if you can get these pages to budge even a little when trying to pull them apart. When clay soil hardens and dries out in the heat, it becomes almost cement-like. Wet clay soil does not allow water to penetrate, or drain past the particles to other areas of the soil.
To improve clay soil, add compost or some other organic matter, which will break up the clay and add little air pockets to the soil. If you aren't sure of what you can compost take a look at our guide on what to compost. Do not add sand to clay soils, as that is like adding sand to cement. If you’ve ever gardened in clay soil (I have), you’ll know that clay soil is often frustrating for gardeners.
Silt soil is where you will find the most desirable soil characteristics. It is full of nutrients for good soil fertility, moisture retentive, made up of medium particles, and drains excess water. The biggest problem with silt soils is that they are very light making them more likely to wash away with rain.
You can improve silt soil by amending it with organic matter. Organic matter will help it retain its nutrient density, moisture retention, and reduce its readiness for erosion. Keep your rich soil where you want it.
The last type of soil we’ll discuss today is loamy soil. Simply put, loamy soil is ideal gardening soil because of its high nutrients and high water retention, but can drain excess water and lacks the negative effects of sandy or clay soil. Loamy soil is easy to work with and fun to simply run your hands through.
Because of its excellent composition, loamy soil doesn’t need to be amended to change its characteristics like the other types of soil. However, it’s always a good idea to top it off with some good organic matter each year. This will help maintain your soil texture and replenish the soil that has eroded away.
Check out our article about amending soil to find out why and how to amend your soil, as well as the benefits to doing so.