Santiago’s portable greenroofing machine, running on B-99 biodiesel.

Plant material from Wallace Hansen Nursery and Sevenoaks Nursery.

Specialty soil mix from Phillips Soil Products in Canby.

Shooting the soil up on the roof.

Students helping to get the rock ballast up on the roof.

To avoid soil compaction we used playwood “lily pads” to get around.

The innovative temporary irrigation system.

All finished.

Three weeks later.

From the Wikipedia entry for green roofs: “Also known as “living roofs,” green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife, and helping to lower urban air temperatures and combat the heat island effect.