How To Identify Your Soil Type
You can learn a lot about your soil by simply running it through your fingers.
Getty Images
Healthy soil is the key to growing a beautiful and thriving garden. Building and nourishing the soil begins with getting to know what type of soil you have. Knowing your soil type will help you in selecting plants best suited for your growing conditions and guide soil amendment decisions. Soil type also affects how long and how often you need to water the garden and plays a role in nutrient availability. Learn how to identify your soil type so you can hone garden management strategies and build a healthy base for your plants.
The Building Blocks of Soil
Soil is composed of solid particles and pore spaces. Pore spaces make up approximately 50% of soil by volume. They act as conduits for air and water movement through the soil. The other 50% of soil is composed of minerals, organic matter, and microbial life. Organic matter is derived from decomposed plant and animal residues, essentially nature’s compost. Soil microbes include insects, fungi, bacteria, and earthworms, many of which act as decomposers to break down these plant and animal wastes into compounds usable by plants. The mineral component of soil is made up of clay, silt, and sand particles. The relative amounts of these materials are what we use to describe the texture of a soil or soil type.
How To Identify Your Soil Type
The best way to learn about your soil is to collect a sample for testing and bring it to your local County Extension office for analysis. The results will tell you not only about the soil texture, but also pH and nutrient availability, and provide recommendations for amending soils and fertilizing plant material. Garden centers also sell a variety of products for testing soil pH and primary nutrients.
However, you don’t need any special tools to identify your soil type—just your hands. Soil scientists call this the “texture by feel method” which is quite a precise description. Here’s how it works:
Scoop a handful of soil into your hand.
Moisten the soil slightly with a watering can (unless the soil is already damp).
Squeeze the soil into a ball.
Bounce the ball gently in your hand.
Use your thumb to rub the soil against your fingers.
As you work the soil, pay attention to how it feels in your hands. How well does the soil form a ball? Does the ball hold together or fall apart? When you bounce the ball in your hand, does it continue to hold, or does it break easily? As you run the soil between your fingers, consider the relative grittiness or smoothness of the soil. When you rub the soil between your thumb and fingers does it form a ribbon or simply crumble? All these questions will help you determine the texture or type of soil.
Texture and Feel of Different Soil Types
When we describe soil type, we are describing the dominant mineral particles. A soil is seldom composed of 100% clay or 100% silt, but some combination of two or three mineral elements, along with organic matter. From the standpoint of soil type, one of these minerals will be most prominent. Use the following to determine what type of soil you have from the texture by feel method.
Sand
Sand particles feel gritty between your fingers. Sand doesn’t hold together well as a ball. It may make a ball when damp, but it will break apart readily when you bounce the soil ball. When you run your thumb through it, sandy soil crumbles.
Clay
Clay particles are very fine (small) and clay soil feels sticky when you squeeze it in your hands. Clay soil forms a ball very easily, you can often mold the soil in your hands. The ball does not break apart when bounced in your palm. The clay particles stick together even when you rub the soil between your thumb and fingers, forming a ribbon.
Silt
Silt is also very fine, with particles intermediate in size between clay and sand. When you make a ball of silty soil, it will hold together well, but break apart when worked in the hand or bounced. Silt soils feel soft and smooth, almost flour-like, when you rub it between your thumb and fingers. It will not form a ribbon like clay.
Loam
The word loam is used to describe soils with a good mixture of sand, silt, and clay, as well as organic matter. This is the soil type we all wish we had for gardening! Loams can have more sand or more silt or more clay, but they generally feel smooth between your fingers. A moistened ball of loam sticks together well but breaks apart readily when bounced or when you run the soil between your thumb and fingers.
Why Soil Type Matters
One of the main differences in these soils is the relative size of the individual particles. Clay soils have the smallest particles, followed by silt. Sand has the largest particles. These different particle sizes impact the size of the pores in the soil. Remember, air and water move through the pores. As you would imagine, coarse textured sandy soils with larger pores allow water to enter the soil more rapidly than fine textured clay soils with smaller pores. Water also drains more quickly from soils with large particles, while those with fine particles retain soil moisture longer.
These soil characteristics impact how we irrigate according to soil type. When irrigating, water should be applied only as quickly as it can be absorbed by the soil. This is one reason drip irrigation is so effective at saving water, especially in clay soils. It delivers water slowly, allowing that water to infiltrate rather than running off across the soil surface. Irrigation frequency also varies by soil type. Because they drain so freely, sandy soils need to be irrigated more often than fine-textured soils. Clay soils retain water more effectively and therefore can be irrigated less often.
Soil type also affects what plants will thrive in our gardens. Some plants do not tolerate clay soil, while others need more moisture than sand can provide. By getting to know your soil type, you can get your garden off to a good start by selecting plants that match your unique conditions.
For more Southern Living news, make sure to sign up for our newsletter!
Read the original article on Southern Living.
