Washington Rock’s organic topsoil is unique in the Tacoma area.
Mined from earth that has been undisturbed for thousands of years, our topsoil is a virgin mix of sand and organic matter. This is important because we know exactly where our material comes from and what’s in it—something that is not true for topsoil suppliers who import topsoil from many different job sites.
What is the process of mining virgin topsoil?
Clearing & Grubbing. First, the vegetation has to be removed from the surface of the topsoil. This is called clearing. Then the remaining roots have to be removed. This is called grubbing.
Grading. After plants and roots have been removed, a machine pushes the topsoil layer into piles.
Pre-mixing. A loader is used to add compost to the topsoil piles and mix the materials together. The compost adds nutrients to the soil. If the topsoil doesn’t have enough sand, sand can also be added to help the topsoil drain better.
Screening. Topsoil is then deposited into a topsoil screening plant. The plant has a screen that removes material larger than 3/8 of an inch, including stones and pieces of wood. The plant also tumbles the pre-mixed material, helping the mix become more uniform.
Delivery. 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.
Watch a video of our topsoil being unloaded at the Tehaleh landscaping yard in Bonney Lake.
For more information about Washington Rock’s residential topsoil products, visit our Residential Topsoil Products page.