Washington Rock’s Basic Topsoil is a naturally organic sandy loam.
It’s a fantastic base material that can be used to mound and build up yards and gardens. We use it to create bulk topsoil blends, but you can also mix in your own amendments like compost, manure, and worm castings.
But where does our sandy loam topsoil come from? Read more to learn about the mining process at King Creek Pit.
This article is the third in a three-part series about topsoil:
- “Choosing a Topsoil Mix for Your Yard & Garden”
- “What is Sandy Loam?: A Basic Guide to Soil Types”
- “Organic Topsoil from Orting: How It’s Mined” (this article)
How Topsoil is Mined
Clearing & Grubbing
Before we can access the topsoil layer at King Creek Pit, we need to remove everything lying above it. That requires first clearing the land. Clearing means removing vegetation like trees, shrubs, and other plants.
Then the remaining roots, stumps, and debris have to be removed. This step is called “grubbing.”
Grading
After plants and roots have been removed, the topsoil layer is finally exposed. A machine like a dozer or scraper pushes the topsoil layer into piles. Before it’s blended with other products and screened, this product is known as Unscreened Sandy Loam.
Pre-Mixing Amendments (Topsoil Blends Only)
To create topsoil blends like 3-Way Topsoil and Garden Mix, we import compost made locally from recycled garden prunings, food products, and vegetable trimmings. A loader operator adds compost to the piles of mined topsoil and uses the loader bucket to manually mix the materials together.
Our 3-Way Topsoil is ⅓ compost and ⅔ Basic Topsoil by volume while our Garden Mix is ½ compost and ½ Basic Topsoil by volume.
See how the loader operator blends materials in the video below:
Screening
Topsoil is then deposited into a topsoil screening plant. The plant has a screen that removes material larger than 3/8″, including stones and pieces of wood. The plant also tumbles the pre-mixed material, helping the mix to become more uniform.
Stockpiling
Conveyors carry the finished product away from the plant and deposit it in piles on the ground. This product is ready to be loaded onto trucks and delivered to homeowners.
Delivery
We contract with local haulers to deliver our topsoil products to projects throughout the Puget Sound region. We supply material via solo dump truck, truck and trailer, side dump, and transfer.
Our products have been used to sculpt newly graded yards, to grow vegetable gardens, to install fields, and more.
For more information about Washington Rock’s residential topsoil products, visit our Topsoil Products page.
Check out other helpful articles on our blog:
- “Choosing a Topsoil Mix”
- “What is Sandy Loam”
- “Clean v. Minus”
- “Comparing Crushed Rock Sizes & Types”
- “How Do I Make a Gravel Surface Wheelchair-Accessible?”
- “How Do I Pick a Gravel Grid Product?”
- “How Many Cubic Yards Do I Need?”
- “How to Find, Vet, and Hire a Contractor Who Can Work with Rock”
- “Should I Put Landscape Fabric Under Gravel?”
- “What are Gravel Grids?”
- “What are the Pros and Cons of Using Gravel Grids?”
- “What Does a Cubic Yard Look Like?”
Washington Rock Quarries is a family-owned business that produces rock, sand, and soil products at Kapowsin Quarry and King Creek Pit in Orting, Washington.
This article was originally published in March 2017 and updated in April 2025.