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Topsoil vs Compost – When and How to Use Each

Good soil is the foundation for all gardening, but it takes careful stewardship to achieve. In this post we’ll cover the difference between topsoil vs compost and how and when to use each!

I’m sure you’ve heard the terms topsoil, compost, 50/50 blend and more, but what do they REALLY mean?

a woman holding a seedling and topsoil vs compost

What is the REAL difference between topsoil and compost?

And when should you use which?

Just like how an infant needs its mother to grow healthily, a new lawn needs quality lawn care from someone knowledgeable.

Let me give you a simple walkthrough of the difference between topsoil and compost so that you know which to use in each case.

Topsoil vs Compost

Understanding Topsoil

In a nutshell, top soil is the topmost covering of the land of the Earth.

As the name implies, it is the top layer of soil that is a nutrient-rich layer that can help in boosting healthy plant growth.

High-quality topsoil is an ideal environment for a plant to grow in.

However, healthy soil is not easy to find nowadays.

Routine plowing, run-off, mowing and mismanagement have left most available topsoil devoid of essential nutrients.

There are different types of soil and not every type contains enough nutrients that are necessary for plant growth.

This is why for places with poor quality soil, adding organic compost to the soil is important to make the soil healthy again.

In some areas, topsoil can be covered by fill dirt, which is really unhealthy for plant growth.

clay soil

Different Types of Topsoil

There are three different types of topsoil, and not every soil is nutrient-rich soil.

The layer of topsoil is usually a combination of sand, silt, clay, and other organic matter that has broken down over time.

Every type of topsoil has different physical characteristics, each making them best for different uses.

To evaluate your own soil, check out my post on 6 ways to test your soil at home.

Sandy Soil

The first kind of topsoil is sandy soil.

Sandy soil is the type of soil like what you see on the beach or in the desert.

The two main things that make up sandy soil are particles of minerals and fine rocks. Because of this, sandy soil is the best option for architectural and engineering uses.

When we look at it from a gardener’s point of view, sandy soil is poor soil.

But that doesn’t mean it can’t be used for gardening. Succulents grow best in this type of soil.

Since it doesn’t hold much water, it can be the right soil for plants that don’t need much water.

However, sandy soil isn’t the best soil for growing plants since it cannot hold much nutrients and water which is needed by most plants.

Flower beds that use sandy soil should always be checked when watering and fertilizing.

topsoil vs compost for vegetable garden

Clay Soil

The next type of topsoil is clay soil.

Clay is made up of organic materials that have decayed over time mixed together with powdered rocks.

Over time and due to weathering, the two mix up and create layers of topsoil that were traditionally used for clay pottery, bricks, dishware, cooking pots, and others.

Clay soil has a better quality in growing plants as compared to sandy soil.

Because of its water retention ability, this soil is a good growing medium for plants.

However, because it is compact, the addition of compost to the top layer of the soil is an easy way to put clay to good use for a healthy garden. 

Topsoil vs Compost – Loamy Soil

Lastly, the third type is loam. Loam soil is a mixture of silt, sand, and clay. This makes it an ideal soil for the garden as it contains some of the attributes that each type of soil has.

If you want gardening advice, here’s one—if you’re looking for the right type of soil for your garden, this is what should use.

Because of its good drainage, it allows plant roots to breathe and get enough water they need to grow, making it an ideal soil to use for your next garden project.

Familiarizing yourself with the kinds of soil is the best way to start your own garden.

However, it is no big deal for those who have existing soil on their lawns already.

People with an existing lawn can still give their lawn a new look. This is where the power of compost can be seen.

a large compost pile

Understanding Compost

Good topsoil may be difficult to find nowadays, but that’s okay.

This is the main reason why organic compost is here!

In simple words, compost is a soil amendment made of decomposed organic matter.

It is added to the soil to encourage growth again and to add the necessary organic material to the soil again.

Adding compost also improves soil quality, making it the best soil conditioner there is. Keeping a compost bin doesn’t necessarily need a large area, so you can do it even in a tiny home!

Check out our complete guide on starting your own compost pile!

You can make your own compost at home simply by adding different things like food scraps, wood chips, grass clippings, yard waste, and more to your compost bin.

Just make sure that you have enough layers of different materials of greens and browns in your compost bin to allow them to decompose nicely.

compost and topsoil to build the perfect garden

The good thing about compost is that it is able to kill weed seeds because of the heat inside. You can also add decayed sphagnum moss to your compost pile as a source of carbon.

Both carbon and nitrogen are needed for the composting process to be done perfectly.

Although it is tempting to start new garden beds with pure compost, this isn’t a perfectly good idea.

For best results, you can add a few inches of a quality compost product to a few inches of topsoil.

Unlike what other people think, you don’t need to mix compost with the soil. You just have to add a layer of compost on top of the soil.

When the rain comes or when you water your garden, the compost tea seeps into the soil and starts to do the magic.

By now, I’m sure you understand that the general purpose of compost is to alleviate the soil’s health. But, it is important to use compost in moderation.

Adding too much compost to the soil might do more harm than good.

The right amount of compost that a vegetable garden or a flower garden needs is just about one to three inches. As a general rule, 1 cubic yard of soil needs 27 bags of 1 cubic foot of compost.

tomatoes growing in a healthy garden

Garden Soil vs Potting Soil

When you are adding new soil to a garden, as a novice gardener, it is important to choose the right type of soil. Most garden centers offer two soil products—garden soil and potting soil. Each one is good and has its own use.

Garden soil is soil that has been treated with soil amendment and has been mixed with native soil.

It is usually made of topsoil blended with compost.

Because garden soil has much organic matter, it has good water holding capacity and is loose enough to be used for garden beds.

On the other hand, potting soil is best used in gardens for containers.

This type of soil works best in potted houseplants or window boxes. This is because potting soil can provide more balance of moisture for closed environments as compared to garden soil.

Potting soil mixes usually have a mixture of peat moss in them, together with ground pine bark, and perlite or vermiculite.

This soil also has plant food in it, making it a suitable soil for potted containers.

Before starting or mending a garden, it is important to understand the science of soil first. You can not simply top dress your lawn with compost simply because you read it from an article about compost applications from the internet, right?

That isn’t really the best way to get a lawn as beautiful as the grass in a golf course. Having small areas of low spots in your garden can be irritating, too.

Some just place fill dirt on them to fill the hole. Sure, it works. But, getting a gardener’s advice should be better.

To understand gardening more, follow our site. You can purchase grass seeds and finished products from True Leaf, as well as find quality products of the dynamic soil trio—topsoil, organic compost, and organic mulches.