Topsoil vs. Fill Dirt: What is the Difference?


What is Fill Dirt?


Fill dirt is a type of dirt commonly used to fill depressions or holes in the ground to create a level surface for various landscaping projects. It typically lacks organic matter and is often composed of subsoil, clay, sand, and rocks. Fill dirt is also used in construction projects to create a stable base for foundations, driveways, and roads. It can also be used to build up the grade of land for landscaping and gardening purposes. Fill dirt is often obtained from excavation sites, where it is dug up and then transported to the desired location for filling.

Topsoil Vs. Fill Dirt: Which is Best? Infographic by Splendid Landscapes


Composition of Fill Dirt

Fill dirt is primarily made up of subsoil, which is the layer of soil underneath the topsoil. It may also contain varying amounts of clay, sand, and rocks, depending on its source and location. In addition, fill dirt may also contain organic matter, such as decaying plant material or small roots. This can provide nutrients to the soil and help improve its fertility.

The exact composition of fill dirt can vary widely, depending on where it is sourced from and what materials are mixed in during its production. It is important to consider the specific requirements for your project and choose fill dirt with the appropriate composition to ensure the best results.

Uses of Fill Dirt

Fill dirt is primarily used to fill holes, level uneven ground, and create a stable base for construction and landscaping projects. It is commonly employed for filling and compacting areas where a solid, stable foundation is needed.

While fill dirt is not suitable for growing plants, it is an important material for creating a stable and level surface for construction and landscaping projects. It is typically less expensive than topsoil and is widely used in various earth-moving applications.

a pile of fill dirt


Differences from Topsoil

Fill dirt differs from topsoil in its composition and intended use. Unlike topsoil, fill dirt usually lacks organic matter and is not suitable for supporting plant growth. Its main purpose is to provide structural stability and fill voids in the ground.

What is Topsoil?

Topsoil, on the other hand, is the uppermost layer of soil, containing the highest concentration of organic matter and microorganisms. It is essential for supporting plant growth and providing nutrients necessary for healthy vegetation.

pile of soil resting in two hands


Composition of Topsoil

Topsoil consists of a mix of organic matter, such as decomposed plant material and humus, along with mineral particles, providing a fertile environment for roots to thrive.

Uses of Topsoil

Topsoil is commonly used in gardening and landscaping to promote healthy plant growth, improve soil quality, and enhance the overall appearance of outdoor spaces. It is essential for establishing new gardens and nurturing existing vegetation.

Differences from Fill Dirt

Unlike fill dirt, topsoil contains organic matter, making it an ideal medium for supporting plant life and promoting healthy root development. It is not primarily used for structural purposes like fill dirt but rather for enhancing the fertility and vitality of the soil.

Which is Best for Your Landscaping Project?

When deciding between fill dirt and topsoil for a landscaping project, it is crucial to consider the nutrient content, soil quality improvement, and impact on plant growth.

women pondering about which is best for her landscaping project



Nutrient Content

Topsoil offers a rich source of nutrients and organic matter essential for plant growth, while fill dirt lacks these crucial elements, making it unsuitable for supporting most vegetation.

Improving Soil Quality

Topsoil plays a pivotal role in improving soil quality by enhancing its fertility and providing a conducive environment for beneficial soil organisms. In contrast, fill dirt primarily contributes to structural stability and leveling but does not enrich the soil composition.

Enhancing Plant Growth

For promoting healthy plant growth and sustaining vibrant landscapes, topsoil is the preferred choice due to its ability to support root development and optimize nutrient uptake. Fill dirt, being devoid of essential nutrients, does not foster optimal plant growth.

Uses in Gardening and Landscaping

Both topsoil and fill dirt find specific applications in gardening and landscaping, catering to different requirements for outdoor projects.

Enhancing Drainage

Topsoil aids in enhancing drainage and moisture retention, especially in areas with poor soil structure, promoting healthier root systems. In comparison, fill dirt is used for filling voids and creating a level surface but does not actively contribute to drainage improvement.


Backfilling Projects

Fill dirt is commonly used for backfilling projects, compacting areas, and creating a stable base for construction and landscaping elements, while topsoil is utilized for promoting fertility and supporting plant life in gardens and green spaces.

New Grass Establishment

When establishing new grass or lawn areas, topsoil is essential for providing the necessary nutrients for seed germination and sustaining healthy grass growth. Fill dirt, with its minimal organic content, is not suitable for nurturing new grass and sustaining lush landscapes.

So What Should You Use?

In conclusion, understanding the distinctions between topsoil and fill dirt is crucial for making informed decisions in landscaping and gardening projects. While fill dirt serves structural and leveling purposes, topsoil plays a vital role in nurturing healthy vegetation and promoting optimum soil fertility. Selecting the appropriate soil type based on the specific project requirements is essential for achieving successful and sustainable outdoor spaces.