Topsoil, Mulch, & Compost: What’s the Difference and How to Use Them (2024)

Topsoil, Mulch, & Compost: What’s the Difference and How to Use Them (1)

When landscaping your yard or setting up a new garden, it’s important to know how to use certain organic materials to get the most out of your plants. Three of the most commonly used materials are mulch, compost, and topsoil.

Understanding the difference between this soil trio is essential, but even more important is knowing which to use, where, and when.

How to Use Topsoil and Compost

Topsoil is the upper, outermost layer of soil that is usually composed of the top few inches. It has the highest concentration of organic matter and microorganisms and is where most of the Earth’s biological soil activity occurs. Plants generally concentrate their roots in this layer and obtain most of their nutrients here.

The Need for Topsoil

In the days of our grandparents, the topsoil was naturally very thick and deep but due to land clearing, over-farming, and other unsustainable agriculture practices, our soil has been depleted. So much so, that in many places across the country, there is little to no topsoil left at all.

If you are preparing a site for planting edibles or ornamentals, it’s important to start with good soil that is high in nutrients and will feed your plants as they grow.

The easy way to accomplish this is to simply buy prepared topsoil, then add it to your site before planting, mix it into the existing soil, and begin planting. If you have time, however, you can create topsoil by yourself. Toss organic matter like grass clippings, discarded fruit, leaves, etc. into a pile where it receives air and water it will naturally break down, resulting in compost. Mix the compost into the top layer of your planting area and you are good to go.

Difference Between Topsoil and Compost

Compost and topsoil are essentially the product of decomposed organic matter. They are both high in nutrients and beneficial organisms. They are both an excellent addition to your garden, but are they the same? Not really.

While they share many of the same attributes, compost and topsoil differ in their application. Compost is often only used as an organic amendment, the result of letting organic materials breakdown until they are a fine texture.

Compost is usually used more as potting soil, a top-layer fertilizer to your plants, or to amend your current soil. Whereas topsoil is better for building up your soil level or as a landscape filler. In fact, many times when you order topsoil in bulk, what you get is dirt with some organic matter blended in.

As a result of the collection, reduction, and recycling of tree and land clearing debris, Gaston Mulch and Soil produces topsoil as the biomass material decomposed and screened, creating topsoil that is the best of both worlds.

How to Use Mulch

After you’ve created a base layer of topsoil, then enriched it with compost, you need a cover to keep it cool and moist, and prevent weeds from competing with the more desirable plants in your garden.

This is where mulch comes in. In addition to beautifying your landscape, mulch helps prolong the life of your plants and keep your soil intact. Over time, mulch will break down and effectively become topsoil but it shouldn’t be used in lieu of topsoil. That said, while you could leave your topsoil uncovered, it is wise to cover it with mulch to avoid erosion from the rain and overheating from our hot sun.

Gaston Mulch, Topsoil, and Compost

While you may not have considered all the differences between these different soil amendments, it’s important to use them properly.

To reiterate: Lay a base level of topsoil, enriched with compost, and cover it with mulch.

At Gaston Mulch and Soil, we create our compost, topsoil, and mulches from the highest quality, recycled tree debris. If you are starting a garden, or refreshing your landscape, contact us. We’d love to help with your project.

Topsoil, Mulch, & Compost: What’s the Difference and How to Use Them (2024)

FAQs

Topsoil, Mulch, & Compost: What’s the Difference and How to Use Them? ›

Compost is usually used more as potting soil, a top-layer fertilizer to your plants, or to amend your current soil. Whereas topsoil is better for building up your soil level or as a landscape filler. In fact, many times when you order topsoil in bulk, what you get is dirt with some organic matter blended in.

When to use topsoil vs compost? ›

Compost is usually used more as potting soil, a top-layer fertilizer to your plants, or to amend your current soil. Whereas topsoil is better for building up your soil level or as a landscape filler. In fact, many times when you order topsoil in bulk, what you get is dirt with some organic matter blended in.

Do you put compost on top of the soil or mix it in? ›

Add compost to soil before you install landscape plants. Spread a 3- to 4-inch layer of compost over the area you intend to plant. Mix the compost into the soil as deeply as possible. Then install new plants into the amended soil.

Should I add topsoil or mulch? ›

A well-dressed lawn or landscape will include layers of different materials that create an ideal environment for healthy growth. First is the topsoil, then the compost and, finally, a mulch to blanket it all.

Do you need both compost and mulch? ›

Mulches can be applied atop compost or leaf litter to suppress weeds, add organic material, and reduce the evaporation of moisture from the soil. The layer of leaf litter or compost will provide extra nutrients and break down more quickly than the mulch. Add a maximum of 2–3 inches of mulch to your garden.

Does grass grow better in compost or topsoil? ›

If you're trying to grow a thick, lush carpet of grass, both topsoil and compost can be effective. Either one can be used to address bald spots in your lawn, by adding two to three inches' worth of topsoil or compost to the area and incorporating it into the existing soil to encourage grass growth over time.

How long does it take compost to turn into topsoil? ›

Compost is ready to use after anywhere from one to 12 months, depending on the size of the materials placed in the compost system, the degree of management, and the intended use. Compost that will be used as a top dressing or mulch can be applied after the least amount of time.

Can you put too much compost in your garden soil? ›

More commonly, soils that have received excess compost tend to be too basic (pH above 7). It is more difficult to acidify soil than to make it more basic, but there are a few things that growers can do: Stop adding compost to prevent the continual addition of cations (positively charged nutrients) to your soil.

Will compost turn into soil? ›

Compost does not become soil, but it does become an important component of healthy soil. Compost is classified as active soil organic matter because it is still decomposing. As compost decomposes, it becomes stable soil organic matter, which can survive in the soil for decades.

Can you plant directly into compost? ›

Compost is one of the best garden amendments available. You can plant in straight compost, but I suggest incorporating it into your sandy garden soil or mixing it with other additives if you want to use it for container plantings.

When should you use topsoil? ›

You can apply topsoil anytime, but most gardeners like to add it in spring before planting. In the fall, it may also be added as a top dressing that will allow nutrients to break down into the soil.

What is topsoil best for? ›

It's best to use it wherever you're lacking soil, for example, to fill in a low spot in your lawn, or as a base layer in a new garden that's missing a foundation of soil. If you use topsoil in a garden, you'd still have to add additional compost or manure to help your plants thrive.

Should you put topsoil over grass? ›

While it's possible to apply topsoil over grass seed, it's crucial to ensure the roots can still reach the soil beneath the new layer. Proper preparation and seeding techniques play a vital role in the success of this process.

Why would you not want to use compost as mulch? ›

Because the uses for compost and mulch are different—soil fertilization and amendment vs. soil covering—it is usually not a good idea to use them interchangeably.

What happens if you don't use compost? ›

If you don't compost and send food down your garbage disposal or trash can, this contributes to greenhouse gas emissions, loss of nutrient-rich soil, loss of biodiversity, and more consequences. Composting your food waste is an important habit to help the environment.

Do I need soil or just compost? ›

Growing directly in compost is not usually recommended. Water retention and support may be lacking in a 100% compost growing medium. Mixing compost with topsoil or potting mixes provides all the benefits of compost and your garden soil or potting mixes. You can make your own compost or purchase it in bulk or bags.

Should I top dress my lawn with compost or topsoil? ›

How to Add Top Dressing to My Lawn. In the spring, apply 0.25–0.5 inches of top dressing after mowing your lawn low with compost, sand or topsoil. The best choice depends on your current soil and issues. Compost is a great all around option for both helping with drainage and providing organic material.

Can I use compost in place of topsoil? ›

The rule for topsoil is that for general projects, it is the perfect option to get your plant's growing well. Now compost works really well, but for slightly different projects. If you are planting into pots then the plants will need extra nutrients because they are in a confined space.

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