Frequently Asked Questions

In general, a depth of 3 to 6 inches of soil is needed for roof top gardens, or green roofs.  Calculating the area of the garden and multiplying by the depth can give you a total volume (i.e. 10 feet x 3 feet x 6 inches divided by 12 = 15 cubic feet or 0.56 cubic yards)

Extensive green roof top gardens offer a shallower depth for planting media.  Intensive green roofs support deeper rooted plants such as grasses, flowers, shrubs, and even trees.  Agricultural or farming can be another blend of soil with more nutrient availability for crops. 

A special lightweight soil mix is manufactured for use on green roof projects.  Normal topsoil and planting mix will become too heavy to support roof top gardens.  The Green Roof Soil Mix is designed to be lightweight, drain well, and retain enough nutrients for roof top plants.  There are even variations of the roof top soil blend to meet specific plant and drainage needs. 

River Sand, Inc. produces and supplies green roof soil in bulk or bagged in one-ton (supersack) bags for projects.  Bulk Green Roof Soil Mix is designed for roof top gardens.  Local delivery saves time and money. 

Green Roof Soil Mix is a type of engineered soil.  Engineered soils are a soil that is specifically blended with different types of soil components (i.e. lightweight aggregate and compost) to achieve certain soil characteristics such as infiltration, pH, or organic matter content.