Guide to Understanding Soil Types

Wondering what to plant to get the most out of your yard? The right grass, shrubs, flowers, and other greenery depend heavily on the type of soil you have. That’s right, not all turf is created equally! Soil is more than just dirt. While the makeup changes with locations and there are different soil textures, the average soil consists of four components. 

4 Key Soil Components

  1. Minerals (sand, silt, rocks, clay) – 45%.
  2. Water – 25%.
  3. Air – 25%.
  4. Organic matter (both living and dead) – 5%.

Soil is created when the solid elements are weathered or broken down into small pieces, over many years. Minerals are a bit less than half of the soil; organic matter about 5%. Air and water split the other half. The water volume will vary depending on the type of soil and how recently it has been irrigated. Air pores are necessary for air and water to bring nutrients to the turf and down to the root of the plant.

A good, fertile soil sustains healthy crops, grasses, and other plants. 

There are generally four accepted types of soil. Let’s take a look at each one, including which soil gives the best yield and the plants that are best suited to them.

Soil Types

  • Sandy Soil
  • Clay Soil
  • Silty Soil
  • Loamy Soil

Sandy Soil

Sandy soil drains promptly, but often lacks organic material. Credit: Peaceray, CC by SA 4.0

Sand is a loose granular material made up of soil particles created over thousands of years when rocks break down from erosion and weathering. Sandy soil is gritty to the touch and is quick to warm up in the spring. It’s easy to cultivate but doesn’t hold water well, as it drains quickly. This also causes nutrients to wash out, keeping them from reaching the plant’s roots. To improve sandy soil, you can work organic matter into it. You can also add mulch, like wood chips, leaves or hay around the plant to hold in moisture.

Red, tall, and hard fescue grasses grow well in sandy soil, and if you’re looking for a low-maintenance lawn, hard fescue is best. As far as plant growth, shrubs like broom, tree mallow, and sun rose grow well in sandy soil. Flowering plants like tulips and hibiscus are your best bets to add accent colors to your yard.

Clay Soil

Cracks are a hallmark of clay soil, which readily absorbs water, but shrinks and cracks as it dries out.

Clay soil can be a tough nut to crack when you’re trying to grow vegetation. It’s made up of tiny mineral pieces and lacks organic material. This makes it lumpy and sticky when wet and hard as a rock when dry. Clay particles are tough to cultivate. It is, however, very fertile as it retains nutrients and has a high water holding capacity. The necessary element it lacks? Air. So how do you work with clay soil? Aeration. Perforating the soil with small holes lets air, water, and nutrients penetrate the ground and reach the roots of grass or plants. Compacted soils, like clay, need regular aeration. 

Ryegrasses and fescues are your best bet for growing a lawn in clay soil. You should start working organic matter into the ground at least two months before planting. Flowers that grow well in clay are asters, Helen’s flower, bergamot, and flowering quince. Horticulturist Andy McIndoe has won 70 consecutive gold medals at the Chelsea Flower Show. He points out, “plants like clay soil a lot more than gardeners do.” He recommends planting flowers and shrubs in early autumn to give them time to establish.  “Clay soils can dry out and bake hard in the summer. Planting in spring may be difficult if the ground is wet and heavy.”

Silty Soil

Somewhere between the particle sizes of a grain of sand and a speck of clay, silt consists of rock and mineral particles. It’s smooth and somewhat slippery to the touch. Silty soil drains well yet holds in moisture and is more fertile than sand or clay but it’s heavier than sand and easily compacted. To improve silty soil, add an inch of organic material as topsoil each year. You can avoid compaction by reducing tilling. 

Many types of turf grasses thrive in silty soil (especially after adding organic matter). But if flooding leaves heavy silt deposits on top of your lawn, you may need to re-establish it by aerating and then overseeding. 

Silty soil is great for plants like mahonia, New Zealand flax, and ornamental vine, as well as most fruit and vegetable crops. Some trees, such as willow, birch, dogwood, and cypress also flourish in silt because of the adequate drainage.  

Loamy Soil

Loam is the king of all soils! It crumbles easily and is made up of nearly equal parts silt, sand, and clay. Loam holds moisture and yet drains well. Its many pore spaces make it easy to cultivate and retain nutrients. Loam allows plant roots to spread deep into the earth, keeping the plant grounded during high winds and heavy rains. The deep roots also help keep the soil from eroding. 

Loam is good for growing nearly all types of turfgrass, but fescues and ryegrasses work especially well. As far as other vegetation, wisteria, dogs-tooth violet, black bamboo, and delphinium thrive in this type of soil. If you’re not lucky enough to have loamy soil, you can create it by adding compost, grass clippings, or shredded tree bark to your existing turf. 

Despite the kind of soil in your yard, it’s possible to grow a luscious lawn. The size of the particles in your turf determines how much work you’ll need to do. Loam soil is best, but understanding soil structure, adding organic matter, using aeration and planting the right vegetation will give you the yard and garden of your dreams!

Main image credit: Josh Larios, CC by SA 2.0

author avatar

Written by Danielle Bradley

Danielle Bradley is a botanist who experiments with native plants from every region in the U.S. She’s dedicated to companion planting without the use of pesticides. Her own garden is filled with a variety of colors and textures.

About Wikilawn

Wikilawn’s mission is to provide the best resources and information to help you enjoy your outdoor spaces the way you want. Whether you are a DIY, lawn-loving, gardening guru, or someone who wants help in picking a local lawn care professional, we can smooth your path to a beautiful backyard!

About Wikilawn

Wikilawn’s mission is to provide the best resources and information to help you enjoy your outdoor spaces the way you want. Whether you are a DIY, lawn-loving, gardening guru, or someone who wants help in picking a local lawn care professional, we can smooth your path to a beautiful backyard!

More Resources