What is Engineered Soil?

Engineered soil is manufactured soil consisting of sand, silt, clay and organic amendments. We design custom-blended soil mixes to meet project requirements with characteristics tailored to your specific purpose.

Engineered soil is used in a wide range of applications, including landscaping, horticulture, green roofs, athletic fields, rain gardens and more. At Plaisted, the following Garden Mixes are available for your use:


CU Structural Soil
Engineered Soil

Green roofs are part of the healthy city movement, absorbing noise pollution and creating a peaceful meditative environment with an aesthetic appeal on building rooftops. Plus, they’re helping to increase property values.

We blend 3 type of rooftop materials. Depths vary depending on what types of plant materials are going to be used and what the roof weight-load is designed to handle:

  • Extensive mixes are generally used at a 3″ to 6″ depth
  • Intensive mixes are generally 6″ to 12″ or more in depth
  • Turf mixes are 6″ to 12″


Excellent drainage properties—Meets MPCA Stormwater Manual Guidelines

Our homogeneous blend of washed clean construction sand (70 to 90%) and sphagnum peat (10 to 30%) allows water to be collected from previous and impervious surfaces while filtering out sediment, pollutants and harmful chemicals.

The organic matter content in this engineered soil mix also allows for water to be stored in the soil short-term and helps maintain your garden by allowing clean water to infiltrate the soil and subsoil slowly, thus recharging groundwater.

To learn more about this unique product, see our literature sheet below:


Our precisely-mixed combination of washed construction sand (70 to 90%) and organic leaf compost (10-30%) provides a full array of benefits for a variety of applications. Collecting water from previous and impervious surfaces, the rain garden compost mix filters out toxins, pollutants and sediment.

This blend captures water in the soil for short-term plant growth and allows clean groundwater to seep into the surrounding soil, creating a natural cycle that rejuvenates your land.

To learn more, read our overview below:


Plaisted Companies has developed an advanced system for stormwater runoff treatment. This specialized mix of C-33 Concrete Sand and 5% Iron Filings captures an average of 88% phosphate from the water up to 200 meters of treated depth.

This revolutionary engineered soil mix effectively removes pollutants and is excellent for nutrient-impaired waters. Iron-enhanced sand is ideal as an upgrade or retrofit to any existing area and is appropriate for use in cold climates.

For more details on how to use iron-enhanced sand, visit www.pca.state.mn.us.


These engineered soil specifications are designed for use in general roadway planting areas and landscape beds. We blend multiple components together with our Accubender™ to meet the requirements. Custom mixes are available in any ratio of materials needed.

Bringing GREEN to the Urban Landscape with Load-bearing Soil

The 5-state area’s licensed supplier of CU-Structural Soil®

Developed by Cornell University, this patented soil blend:

  • Prevents sidewalk heaving
  • Increases rooting volume under pavement—thus tree longevity
  • Excellent for storm-water capture
  • 35,000 tons of our CU-Structural Soil was utilized

CU Structural Soil Lightrail Plaque