What Is Loam Soil and Why Is It Important?


If you have ever been to a garden center, had a plant-lover in your life, or have a green thumb yourself, chances are you have heard of loam or loamy soil. But what exactly is loam soil, and why is it so important for gardens and plants?

Loam is a type of soil comprised of nearly equal parts of sand, silt, and clay. It’s a robust soil combination which is nutrient rich, allows for easy water drainage and airflow, while also retaining good moisture levels. Plants thrive in these conditions, which makes it a highly regarded soil.

Loam is a coveted soil and for many good reasons. In this article, we’ll tell you all about what loam soil is, how to identify it, what it’s used for, and so much more. Keep reading to learn more about this top-tier soil.

What Is Loam Soil?

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Loam is any soil which is comprised of sand, silt, and clay. The combination of the provides a nutrient rich, easy draining and well oxygenated soil mixture.

  • Clay 20 percent concentration: Clay does a great job of retaining water and nutrients. It can feel sticky to the touch, and its minuscule-sized particles make it impossible to see any grains. Clay soil has little to no aeration, meaning air has a hard time passing through it.
  • Silt 40 percent concentration: Silt has a powdery-like feel to it and retains a low amount of water. While it is possible to see silt particles, they cannot be seen with the naked eye. You would need a microscope or magnifying glass to make out any of the grains. The size of these particles allows for decent aeration.
  • Sand 40 percent concentration: Sand particles can be up to 1,000 times larger than clay. Because of this, sand, and clay act quite differently from one another. Air can easily pass through, and these particles can be easily seen and felt. However, sand does a poor job of retaining nutrients or water.

What is the Texture of Loam Soil?

Loam’s texture will depend on whether it is wet or dry. Loam when dry will break apart and crumble in your hands, almost like a dried brown sugar. When wet, loam feels relatively solid and can be squeezed into a shape and hold. It does not easily crumble apart like a wet sand.

Additionally, the balance between clay, silt, and sand determines a soil’s texture. Loam soil is comprised relatively equally of all three of these textures.

The texture of soil plays a big role in establishing a variety of its qualities. These include the rate at which water and air can move through the soil, the quantity of water that can be retained, and the soil’s fertility and workability.

How to Tell if Soil Is Loamy

To figure out if your soil is loamy, you can conduct a few different tests at home.

Touch Test

The easiest way to identify your soil type is by manipulating it between your thumb and index finger. If the texture feels moldable without being sticky, it is likely to be loam. A soil that contains more sand will not bond together or be moldable, and clay soil will be moldable but very sticky.

You can also use your sense of touch by forming a ball out of your soil. Sand will not maintain a ball shape; silt will loosely form but fall out of shape in an open hand; clay will firmly form a ball; and loam will softly form one, but crumble if any pressure is applied.

Ribbon Test

To conduct the ribbon test, you will need to grab some water and a ruler, and of course, your soil. Don’t worry; you don’t have to run to the craft store for the ribbons—no actual ribbon is required. Here is how to do the test:

  1. Take two tablespoons of your soil and put it in a bowl. Slowly add water to the soil, until it becomes sticky. And we mean slowly, ideally one drop of water at a time if possible, so that the soil does not become oversaturated, making it too wet to work with. Mix the soil with your hands as you do this to ensure that the water is fully incorporated.
  2. Once you have reached the desired texture, create a flat ribbon of soil by squeezing it between your fingers. Continue squishing the soil in this way to make the longest ribbon possible without it breaking.
  3. Use your ruler to measure the length of the ribbon you formed. The length of the ribbon can help determine if your soil is loamy. Depending on the length, you can also determine which ratio is off, and which of the three soils need to be added to the misture to create the loam.
Texture of SoilLength of Ribbon
Sandy<15 millimeters (0.59 inches)
Loam25 millimeters (0.98 inches)
Clay50-70 millimeters (1.97-2.76 inches)

Test Kit

If you would rather not get your hands too dirty, a great way to check your soil’s texture is by using an at-home test kit. The Garden Tutor Soil Texture Testing Jar comes with easy-to-follow, detailed instructions on testing your sample. It is as simple as adding some soil, dishwasher detergent, and water to a container, shaking it, waiting a few hours, and then looking at some soil layers. Voila! You have your ratios.

Laboratory Test

If you want to go above and beyond to get precise insights into your soil, you can always take a sample to a soil testing lab. There they can conduct an in-depth analysis of the physical and chemical makeup of your sample.

Some data that a soil lab test can provide for you include:

  • Particle size
  • Foreign matter
  • Asbestos
  • Nutrients
  • pH
  • e. Coli
  • Mercury
  • Herbicides and pesticides

If you are going to do commercial farming it is recommended to let a lab analyze your soil to get the most accurate results.

If you are someone who learns by watching others, check out the YouTube video below. It covers the key steps for assessing what type of soil you are working with.

Does Loam Soil Drain Well?

Loam soil drains at a desirable rate for most plants and crops. To be exact, this infiltration rate is about 0.5 inches (1.27 centimeters) per hour. The balanced ratios of clay, silt, and sand allow for loam to drain at a moderate pace. Loam’s drainage rate is not so fast that water does not get absorbed, but not so slow that it cannot aerate.

It is sort of like a Goldilocks situation: loam’s drainage rate is not too slow and not too fast, but just right.

Does Loam Soil Hold Water?

Like with loam soil’s drainage rate, this type of soil also holds a desirable amount of water. Unlike sandy soils, it can retain a high enough quantity of fluids so that the roots of plants can be hydrated, but not so much that the plant becomes waterlogged.

Waterlogging happens when soil is oversaturated with water, and there is not an adequate level of airflow provided to the plant’s roots. Over an extended duration, this lack of oxygen means the plant can slowly die. If this continues, the soil’s oxygen depletion can also cause soil fertility to deteriorate.

Luckily, loam does not contain enough clay for waterlogging to be a pressing concern. Its moderate water capacity means it is a considerably drought-resistant soil.

What Is the pH Level of Loam Soil?

Photo by Atthaphol Sileung

A pH value measures the alkalinity or acidity of a substance. The pH scale ranges from 0 being the most acidic to 14 being the most alkaline or basic, with seven being neutral.

Soil pH typically falls between 3.5 and 10. For soil to be considered neutral, its pH value must fall between 6.5 and 7.5. Anything less than 6.5 is classified as acidic, and anything greater than 7.5 is classified as alkaline or basic.

The exact pH of any given soil can be influenced by various factors like water content and other substances in the soil. Still, loam’s pH generally sits around 6.5, making it neutral.

Different plants have different desired levels of their soil’s pH. You can test your soil’s exact pH level using an at-home kit like the Atree Soil pH Meter to make sure your plant is living in the soil it needs to thrive.

What is Loam Soil Used For?

Due to the desirable properties of loam soil, it’s a great all-around choice for most vegetation types. It is not so dense and sticky that plants have difficulty rooting in it, but it is also not so loose with many large particles that nutrients and water just flow through it.

Loam is the most versatile soil option out there. 

What Types of Plants Grow Best in Loam Soil?

There is an endless list of plants accustomed to loamy soil. These include fruits, vegetables, herbs, flowers, and trees and shrubs.

Here are some vegetables and fruits that thrive in loam soil:

  • Lettuce
  • Blackberries
  • Potatoes
  • Blueberries
  • Onions
  • Strawberries
  • Green beans
  • Tomatoes
  • Cucumbers

While these fruits and veggies are delicious on their own, it takes some spices to bump them up to the next level. Luckily, there are a variety of herbs that thrive in loam as well, including:

  • Lavender
  • Thyme
  • Sage
  • Basil
  • Lemon balm

A garden is never complete without a few gorgeous flowers too. Here are some blooming beauties that also adore loamy soil:

  • Daffodils
  • Lily of the Valley
  • Hyacinths
  • Crocuses
  • Marigolds
  • Gardenias
  • Birds of Paradise

Did you know: Christmas trees also thrive in loam soil.

Is Loam Soil Good for Potted Plants?

Photo by Katerynabibro

It can be tricky to find a soil suitable for potted plants. It is important that they can drain well so the plant does not develop root rot, but they also must hold enough water so that the plant can retain moisture and be well hydrated.

While loamy soil checks all these boxes, beware of some differences.

Loam only refers to the texture and combination of particle size in soil. A big difference between loamy soil in your garden and potting soil is that potting soil is usually not made up of soil at all.

Instead, potting soil is made up of peat moss, bark, and perlite. These mixtures are usually sterilized to prevent unwanted microorganisms or bugs from crawling around and destroying your plant. This is a big reason why you don’t want to grab loam from your garden to pot your plants if you don’t pasteurize it first.

However, while the heat kills off all the bad substances, it also harms the good, beneficial ones that help your plants grow to their fullest potential. Without the essential minerals and nutrients they need, it can be difficult for your plants to thrive.

That’s where fertilizer comes in handy. Most potted plants will come with a suggestion on their tags as to how often you should fertilize them, as well as which fertilizers to use. EarthPods Premium Indoor Plant Food is an easy, clean, eco-friendly way to supplement your plant’s nutrients. Think of it as a multivitamin for your houseplant! You can also check out this post that has more information on tips for fertilizing your plants.

What are the Advantages of Loam Soil?

Loam is one of the most favorable soil types and, therefore, has many advantages. We have already talked about some of them but let us take a closer look.

Advantages of loam include:

  • Loamy soil has a great balance of water retention and drainage. There is a fine line between too much water and not enough, so a soil that can maintain this delicate equilibrium is one to be praised. Water and nutrient retention allow the plant to stay in great health, while good drainage prevents excess water from collecting and waterlogging the plant.
  • The mixture of particle size in loamy soil allows for adequate airflow. Like humans, the roots of a plant need oxygen to survive. In soil that is too clayey, oxygen cannot always make it down to the roots, especially if it is waterlogged. Loam allows for sufficient airflow, so the plant receives the oxygen it requires.
  • Organic matter found in loam provides diverse nutrients for the plant. Again, like humans, plants need a variety of minerals to stay healthy. If their soil is nutrient-deprived, the plant might become ill and deteriorate. At the very least, it won’t grow as well as it could. Loamy soil is rich in nutrients, so many plants thrive in it.

What Are the Disadvantages of Loam Soil?

While loam is a special soil type, it is not always perfect. Here are some of the disadvantages of loam soil:

  • Loam retains too much water for some plants. Cacti and succulents need dry, light soil to thrive, so a soil with clay-like loam may cause problems for these plants’ roots.
  • Not all loam is created equal. The composition of loamy soil can vary greatly due to malleable ratios between sand, silt, and clay. Sometimes, a loam will have more clay or silt. If you are not carefully identifying which exact type of loamy soil you’re using, you may be doing more harm to your plants than good.
  • The mixed composition of loamy soil makes it prone to erosion. The small particles of silt and sand found in loam mean that rain, harsh weather, or any disruption of the environment can easily cause the soil to detach and erode.

Is Loam the Same as Topsoil?

Topsoil and loam are related terms but are not to be used interchangeably. Loam can be topsoil but not all topsoils are loam. As we have learned, loam refers to a specific balance of sand, silt, and clay. However, topsoil simply refers to the top layer of soil full of nutrients and microorganisms.

Topsoil is the layer of earth where plant growth occurs. This can be less than 10 inches (25.4 centimeters) in depth or go as deep as 36 inches (91.44 centimeters). The latter, however, would be considered “very deep” topsoil.

How Much Loam Soil Do You Need When Gardening?

Since loam is found in the topsoil, it does not need to be any deeper than this first layer of earth. Ultimately, loam only needs to go as deep as the plant’s roots travel.

For most annuals and perennials, 6 to 8 inches (15.24 to 20.32 centimeters) of loam should be plenty. Larger plants with deeper roots like shrubs and trees should have fertile, healthy soil like loam a foot (30.48 centimeters) deeper than the depth at which the bulb or base is planted.

Can You Make Your Own Loam Soil and How?

It is not as easy as combining the proper ratios of sand, silt, and clay to make your own loam soil. However, it is possible. Making your loam takes patience and consistency.

To create loamy soil, you need to add organic matter, and you need to do it regularly.

Organic matter can take the shape of garden clippings, dead leaves, kitchen compost, or animal manure. Adding these to your soil provides a well-balanced meal of nutrients for your plants to enjoy. It also improves your soil’s ability to retain these nutrients, water, and aerate.

You will need to mix organic matter into your soil at least once a year for several years before you see real results. Obtaining loam and getting your soil into peak health is a process that does not happen overnight.

A great time of year to introduce organic matter into your soil is in the late fall. Add approximately two inches (5.08 centimeters) onto your soil and spray it with water until it is thoroughly wet. Let it rest through the winter. When spring hits, turn the soil at least six inches (15.25 centimeters) deep. This process should be done annually.

Can You Re-use Loam Soil?

Loam soil can be re-used, but you will have to work through some steps before planting another plant in it.

If you want to re-pot a plant, make sure you sterilize your soil effectively before bringing it inside or adding another plant to it. This protects against harmful organisms that might have found a home in your soil.

After growing a plant in soil, the level of nutrients will be depleted than their original state. That is why some sort of fertilizer or organic material must be added back into the soil before using it again. Kitchen compost or other decomposing green material can give your loam the boost it needs to help another plant thrive.

Closing Thoughts

Loam is a type of soil made up of balanced levels of sand, silt, and clay. It is highly regarded due to its ideal balance of all three parts. This combination allows the soil to drain well while retaining the water and nutrients plants need to survive. Most plants thrive in this type of soil as it promotes a uniquely healthy growing environment compared with other soil types.

Here are Some of my Favorite Gardening Products and Tools

Thank you for reading this article. I hope you found it helpful for growing some new plants in your home or garden. Here are some products I like that I hope you’ll also find helpful. These are affiliate links, and I am compensated for referring traffic. But in all honesty, these are the exact product that I use or recommend to everyone.

Soil: For high-quality soil, I really like Fox Farm Ocean Forest. I do all my growing in containers and this soil has worked great for me. I like how they use nutrient-rich contents like earthworm castings, bat guano, and composted crab and fish.

Fertilizer: Currently I am using a seaweed-based organic fertilizer call Neptunes Harvest. This is a great milder fertilizer option if you want to use something organic. If you want a more powerful fertilizer, I recommend Fox Farm Liquid Nutrient Trio, lots of people have had great growing success with this product.

Pruning Shears: Pruning shears are one of the most useful gardening tools to have because it’s important to prune your plants to keep them healthy. The pruning shears I recommend are the Gonicc 8’’ pruning shears. I like them because they are built sturdy and work both on bigger and smaller plants, so you don’t need to have multiple pruning shears.

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