What Is Loam Soil? (2024)

Loam soil is a type of soil that is a mixture of sand, silt, and clay. Loam soil holds nutrients and has a texture that retains water long enough for plant roots to access it, yet it drains well—meaning that the water eventually seeps away so that plant roots do not sit in water and rot.

Without quality soil, plants struggle to survive and usually require supplemental feeding and watering.

Benefits of Loam Soil

Gardeners, farmers, and homeowners desire loam, because it's terrific for growing crops, fruits, flowers, grass, trees, shrubs, and more. The soil texture allows roots to spread quickly, retain moisture, and obtain nutrients.

• Air circulation: Loam soil provides plants with medium-textured soil, allowing air to circulate plant roots; air circulation protects against diseases often found in poorly draining compacted soils.
• Moisture retention: Loam soil's texture helps plants hang on to moisture and keep them well-hydrated.
• Fast-spreading roots: The texture of loam soil also helps the roots spread quickly, allowing for plants to obtain all the necessary nutrients.
• Drainage: Loam soil promotes good drainage, helping plants be healthy and happy.
  

Loam Soil Composition

Loam soil, the ideal growing medium for the vast majority of garden plants, includes three components:

• Sand: 40 percent of the soil
• Silt: 40 percent of the soil
• Clay: 20 percent of the soil

Silt refers to loose, sedimentary material composed of tiny particles that are bigger than clay but smaller than sand. While water drains slowly through clay and quickly through sand, it drains through silt at an average pace. Soil that consists of 80 percent silt is referred to as "silty."

While loam can be present naturally in a garden bed, it's more likely that the native soil will need some help to achieve the ideal composition. Improving garden soil is not quick and easy, but the results are well worth it.

Types of Loam

Loam soils can be classified into subgroups: sandy loam, silt loam, clay loam, and silty clay loam. These types of loam are made by increasing the percentage of that component to make it "sandy," "silty," or to contain more "clay."

Function of Sand, Clay, and Silt in Soil

The sand particles are the largest among loam's three components. Sand does not hold moisture, but it lends good aeration and drainage as a component of loamy soil.

Loam's clay particles are much smaller and are easily compacted. However, clay tends to be higher in nutrients than the other soil parts. That makes clay an excellent material for building bricks but not so great for allowing water, air, and plant roots through.

Silt is a medium-sized particle with better moisture retention than sand but fewer nutrients than clay. Silt helps clay and sand mix more readily, like tempering chocolate.

In addition to providing nutrients and water effectively, loam has a loose, crumbly texture, referred to as being friable. Loose soil allows for oxygen to be present, which is also necessary for root growth. Loam's friable nature also makes it easy for roots to spread out to consume nutrients and water.

How to Create Loam Soil

Good loam soil can be made using topsoil mixed with organic matter. Test the soil for its pH level, nutrients, and organic matter—add lime, fertilizer, and organic matter to reach the ideal ratio for your specific plant before seeding or transplanting.

Although loam combines sand, silt, and clay, adding sand to clay soil (or vice versa) will not create loam. Doing so will result in a material similar to concrete. Rather than immediately creating the correct proportions of sand, silt, and clay, improving soil is best done by adding organic matter. This nurtures soil organisms that transform the soil into a loamy mixture over time.

The decomposing organic material creates the well-draining conditions plants need. Organic matter also attracts beneficial organisms, keeping the soil healthy. Shredded leaves, straw, and finished compost work well to create rich, loamy soil as they decompose.

When to Amend Soil With Organic Matter

Creating loose, loamy, fertile soil is not a one-and-done garden task. Turning your soil into loam is an ongoing process by incorporating organic matter every year. Organic matter is quickly depleted as it decomposes, so amend the soil each season, preferably in the fall. The amount of organic matter to add depends on the balance of the soil.

Laying down a 2-inch layer of organic matter over the garden surface and then working it into the top few inches of soil should do it for most soils. However, if your soil is extremely sandy or predominantly heavy clay, it might need larger amounts of organic matter added several times a season. Instead of bagging fallen leaves in autumn, shred them and add them to your garden beds, where they will decompose and enrich the soil.

Can You Buy Loam Soil?

Loam describes a specific type of texture of the soil and it's something that must be adjusted continuously, meaning there is no loam soil you can purchase as is.

Buying soil in bulk can be a fast and easy way to grow your garden or yard—but it can also be pricey. In addition, while certification programs are offered to help consumers, retailers, regulators, and others identify high-quality soil, they are voluntary now.

Many companies that sell soil are obtaining that soil from construction sites where the soil has been excavated for basem*nts or to level a yard. Generally, soil from excavation sites does not make ideal garden soil. Use that type of soil, known as "fill dirt," for other yard projects but not for growing plants.

If you intend to buy soil, compost, mulch, or other bulk garden material, know something about the company you are buying from. Don't be afraid to ask questions. Bringing in poor soil will not improve your garden and could set you back in your quest for great soil. Trusted and well-known soil companies stand behind their products.