Topsoil Is Essential for Healthy Plants—Here's 3 Ways to Use It in Your Garden

Topsoil is the uppermost layer of soil. It's where essential nutrients, microorganisms, and beneficial insects like earthworms reside, helping provide a healthy environment for plants. Topsoil is also where most of the moisture plants absorb is stored.

Basically, topsoil is where all the magic happens, and it’s incredibly important for the well-being of your garden. To learn more about what makes topsoil so vital, we chatted with garden experts, who explain what topsoil is and how to use it.

What is Topsoil?

As the name implies, topsoil is the top layer of the soil. "It’s the first 3 to 6 inches of your native soil," says Nicole Johnsey Burke, a gardener and CEO of Gardenary Inc. Generally, topsoil is nutrient-rich and permeable, meaning it contains essential nutrients and distributes the water that your plants need to thrive.

Topsoil vs. Garden and Potting Soil

Topsoil is heavier than garden or potting soil. “Topsoil consists of varying amounts of clay, silt, and sand, depending on where you live,” says Burke. These elements are what make the soil rich in nutrients.

Garden soil is topsoil enriched with fertilizer, says Tyler Francis, lead farmer and co-founder of April & Ashley. "Typically, garden soil is used as an amendment," he says. On the other hand, potting soil is made up of organic and inorganic matter and is used for growing plants in containers.

Garden and potting soils often have materials added to render them more nutrient-rich, like vermiculite and peat moss. Both elements make potting and garden soil feel more lightweight and fluffier in texture, but they don’t hold water as well. If your topsoil has a lot of clay, mixing in garden or potting soil can help disperse the clay.

Types of Topsoil

Topsoil is different depending on its geographic location. There are six main types of topsoil: clay, silt, sand, loam, chalk, and peat.

Clay

Clay topsoil has high clay content and is typically heavier than other soils. It stays wet and cold in winter but dries out quickly in summer. According to Burke, clay provides structure for plant roots, but too much clay in topsoil can be challenging, as it doesn't offer enough aeration and drainage, allowing water to collect. 

Clay-based topsoil can also be hard to dig into because it is so densely compacted. In these cases, Burke recommends improving clay-heavy topsoil by adding coarse sand and compost. This will make the soil easier to work with and help plants that might not tolerate clay.

Silt

Opposite to clay-based topsoil, silt is finely textured. Silt holds nutrients and retains moisture well, says Burke. Silt soil contains silt-sized particles, which are larger than clay but smaller than sand.

Sand

Sand-based topsoil is lightweight and easy to dig into, but typically lacks nutrients. This soil type typically needs amendments, like fertilizer or peat moss, to make it more nutrient-rich. “However, having some sand adds porosity and permeability to the soil,” says Burke. Mixing sandy soil with other heavier soils can keep sandy soil from being washed or blown away.

Loam

This type of topsoil combines sand, silt, and clay. "The ideal soil for your garden strikes a balance between these different elements," Burke explains. Thus, you can think of loamy soil as the gold standard of all the topsoil—it is rich in organic matter, offers good texture for planting, and has good drainage.

Chalk

Chalky soil is porous and usually features large amounts of limestone or calcium carbonate, which gives it a higher pH balance. You can amend chalky soil with compost or peat moss to make it more acidic. 

Peat

Peat doesn’t usually occur naturally in large amounts. Instead, it is harvested and added to potting or garden soils. Peat is usually used as a popular soil amendment, says Francis. It’s added to garden soil to improve texture and drainage and provide nutrients.

Ways to Use Topsoil

For Gardening

Topsoil is most commonly used for gardening, including in raised garden beds and flowerpots. “At its core, topsoil is a living ecosystem—full of organic matter, beneficial microbes, and the structure needed to retain water and deliver nutrients,” says Jason Fiddler, a gardener and landscaper at Komplete Landscape Contractors. “If that system isn’t in balance, plants struggle from the start.”

For Patching Lawns

Add a few inches of topsoil to holes or grassless spaces on your lawn, then plant grass seed to fill the patches or holes. If the topsoil you use has enough nutrients, the grass will grow after a deep rain or thorough watering with the garden hose, filling any patchy spots on your lawn.  

For Creating New Green Spaces

Topsoil can also be used to fill in areas that were once barren. Recently, Fiddler added topsoil to an office park for a beautification and landscaping effort. He used well-balanced topsoil full of compost to improve organic content and microbial life for these new green spaces that will hold flowers, shrubs, and trees.

Amending Top Soil

Topsoil can be amended with additives to provide more nutrients at higher levels. An easy way to determine if you need to amend your soil is to dig a hole, fill it with water, and see how long it takes for the water to drain, says Francis. "If it’s taking longer than 30 minutes, add compost and organic matter to enrich the soil, loosen it up, and prepare it for planting." To determine the type of soil amendments your topsoil needs, Francis says to conduct a soil test, which will tell you what your soil is lacking.