Compost vs. Topsoil: What’s the Difference?

Topsoil vs. compost: isn’t it all the same? Well, technically, yes, it’s all dirt. But practically, compost and topsoil have a few differences in nutrient composition and uses. Since they resemble each other quite a bit, it might not be easy to distinguish between the two.

Whether you’re planning to install a new lawn, raise the existing flower beds, upgrade your yard, or maintain your potted plants, you’re probably wondering what will work better for your particular needs. 

In this post, we’ll take a look at the main differences between compost and topsoil, their benefits, and their applications. Should you use one or the other, or both? Scroll down to find out.

What Is Topsoil?

Topsoil is the very topmost layer of soil, high in organic materials and nutrients. Depending on where you gathered the topsoil, it can vary in consistency and ingredients. For example, it might be sandy or clay-like, screened or unscreened, or already have some fertilizers added if you purchase it bagged.

“Topsoil is the top layer of soil where we grow most of our plants. Naturally, topsoil takes hundreds of years to form and contains a whole ecosystem of organisms. Topsoil contains humus material which is similar to compost but also contains minerals necessary for plant growth. You can purchase topsoil that has been stripped from building sights or sometimes manufactured topsoil. These products vary in quality but can be beneficial to improve your soil especially if you have very poor soil.”

Michelle Balz, Author of “No-Waste Composting”

Types of Topsoil

Some of the types of topsoil include:

• Sandy Soil. It drains pretty quickly and doesn’t hold water for long. If you use sandy soil in your garden, you’d want to ensure you’re watering your plants regularly.
• Clay Soil. Unlike sandy soil, clay soil consists of particles that hold water and don’t drain fast. It means that you wouldn’t want to water your garden plants too often if you want to avoid root rotting.
• Loam Soil. It’s a mixture of clay, sand, various organic materials, and slit. Loam soil is very nutrient-dense and can be a perfect choice for your lawn. Z

When you buy topsoil in bulk, make sure to go for screened topsoil. It’s more pricey than unscreened topsoil, but since the latter isn’t a good fit for growing things, it’ll be a smart investment. 

However, if you often require big amounts of topsoil and don’t want to overpay for screened topsoil, you might want to consider acquiring a high-quality topsoil screener and screen it by yourself. 

Note: unscreened topsoil can still be a great base for a garden bed or a specific landscaping project. 

When Should I Use Topsoil?

You’d want to use topsoil to:

• Boost the quality of your garden soil
• Change your existing lawn
• Add depth to shallow garden soil
• Install a new lawn
• Put raised flower beds
• Create new planting areas
• Level uneven spots/surface on your yard or lawn

Pros & Cons of Topsoil

When it comes to your gardening needs, using topsoil has many advantages. Here are some of them:

• It consists of all nutrients plants need to grow healthily
• It improves water infiltration
• It provides the glue material that keeps dirt particles together and holds water for longer
• It helps support beneficial microorganisms
• It lets you reduce the use of fertilizers

Yet, topsoil does have a few disadvantages you should be aware of:

• When you buy topsoil, there is no guarantee it won’t contain weed seeds or is contaminated in one way or another
• Topsoil alone isn’t great for growing plants in pots. You’d need to mix it with potting soil or compost for the best results

What is Compost?

Compost is a mix of natural materials that decompose and become organic matter. It’s made using oxygen, bacteria, water, and organic materials. Compost usually combines green matter, such as food products, with the brown matter, such as dry leaves. These materials break down into rich dark soil, which is mostly used to refresh depleted soils.

“Without complicating it, compost is simply decomposed organic material. For gardeners, it’s the juice that makes gardens glow. If you think of it, it’s like a dash of makeup to bland soil.

Although people often purchase compost from commercial compost makers, making it at home is a better, and cheaper option. You only need to collect all the organic waste from your kitchen, sort them into browns and greens, add water and place it somewhere to decompose. The important thing to note here is that not all materials go into the compost. For instance, adding walnut leaves and plant materials with pesticides poisons the mixture.

In practice, the quality of your compost depends on the quality of organic material used, and the season. Getting good compost during the colder season is hard.”

David Sheppard, Gardening Enthusiast at HVACJudge

Types of Compost

Here are some of the most popular types of compost:

• Composted Manure. It’s raw manure that has been composted and often contains some straw particles.
  
• Composted Green Waste. This type of compost is usually made in a compost bin from garden waste and kitchen food.
• Composted Wood Waste. It’s organic and pure compost made from wood chippings and tree cuttings.

Note: if you plan on using pure compost as a top-dressing for your lawn, you should consider straining it so that it incorporates into topsoil faster. 

When Should I Use Compost?

You should consider using compost to:

• Improve the quality and structure of your soil
• Grow plants in containers, buckets, or window boxes
• Safeguard the base of various shrubs and trees 
• Apply nutrients into your topsoil when planting flower beds
• Boost water retention
• Protect the roots of plants in cold winters
• Save landfills

Pros & Cons of Compost

Here are some of the primary advantages of using compost:

• You can make it yourself by recycling organic food leftovers
• It helps your plants grow properly
• Making it at home is much cheaper than buying fertilizers
• It feeds the soil directly
• It can help you limit the growth of unwanted weeds

Although compost is a great nutrient booster for your soil, here are a few disadvantages you should know about:

• It takes a while to break down entirely and requires quite a bit of storage space
• Since it consists of composting organic matter, it can be very smelly 

Compost vs. Topsoil for a Garden

“For a new garden, it’s always topsoil. Topsoil is better at retaining its structure and holds moisture far longer than compost does. If you’re just creating a small area or small raised bed then go for compost.

Here is a basic rule:

→ general gardening projects = topsoil,

→ pots or hungry plants = compost.”

Michael Alves, Founder of Hello Gardening

Compost vs. Topsoil for a New Lawn

“When planting a new lawn you should first look to improve the depth of your topsoil layer. Adding 2-3 inches of new topsoil is usually enough. Once you’ve laid the topsoil you can plant the grass seeds. Then, topdress your new lawn with a layer of compost.

The compost will cover the grass seeds and protect them from birds and other pests. Eventually, it will work its way down into the new topsoil creating a nutrient-rich soil that will sustain a nice, healthy lawn.”

Veronica Fletcher, Co-Founder of Yuzu Mag

Compost vs. Topsoil: What’s Better?

Using compost soil vs. topsoil for your garden or lawn will mostly depend on your needs and goals. Even though compost and topsoil look similar, they serve different purposes. 

Topsoil is an excellent choice for planting raised garden beds, installing a new lawn, or leveling the surface of an existing one. On the other side, compost is great for enriching your soil with nutrients and promoting the healthy growth of potted plants. Plus, compost is environmentally-friendly, and you can create it by yourself.

Whether you’re just starting your gardening journey or already have years of experience under your belt, you’ll probably use the combination of topsoil and compost quite often. These precious organic materials complement each other and help you maintain your garden and yard in top shape.